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Name: _______________________________________________ ? ? ? ? Electricity ws o level??Date:? ? ? ? Time: ? Total marks available: ? Total marks achieved: ______ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? QuestionsQ1.A student investigates how the voltage across a thermistor varies with temperature.The student keeps the current in the thermistor constant, but varies the temperatures between 20 °C and 100 °C.The diagram shows how the student sets up his apparatus.-3175233045Suggest three changes to this set up that would improve the accuracy of the measurement of the thermistor temperature. (3) 1............................................................................................................................................. ?? ............................................................................................................................................. 2 ............................................................................................................................................. ............................................................................................................................................. 3 ............................................................................................................................................. ?? ............................................................................................................................................. (b) ?What instrument should the student use to measure the current in the thermistor? (1) ............................................................................................................................................. (c) ?The table shows the student's results.(i) ?Plot a graph of voltage against temperature and draw the line of best fit.(5)(ii) ?Circle the anomalous point on your graph.(1)(d) ?(i) ?State the equation linking voltage, current and resistance.(1)(ii) ?At room temperature the thermistor has a resistance of 680 Ω.The voltage across it is 5.9 V.Show that the current in the thermistor is about 8.5 mA.(3)(Total for Question = 14 marks)Q3.A student investigates the efficiency of an electric motor.She uses the motor to lift a mass.The table shows her measurements.(a) ?Calculate the electrical energy supplied to the motor during this time.(2)energy supplied = ........................................................... J(b) ?(i) ?State the equation linking work done, force and distance moved.(1)(ii) ?Calculate the work done on the mass.(2)work done = ........................................................... J(iii) ?State the useful energy transferred to the mass.(1)............................................................................................................................................. (c) ?(i) ?State the equation linking efficiency, useful energy output and total energy input.(1)(ii) ?Calculate the efficiency of the motor.(2)efficiency = ........................................................... J(Total for Question = 9 marks)Q4.A washing machine has an electric motor and an electric heater.The resistance of the heater is 22 Ω.The mains voltage is 230 V.(a) (i) State the equation linking voltage, current and resistance.(1)(ii) Show that the current in the heater is about 10 A when it is working.(2)(b) The washing machine is fitted with a fuse rated at 13 A.(i) Explain why the washing machine is fitted with a fuse.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(ii) When the motor is working, the current in it is 1.74 A.Explain why it would not be sensible to replace the 13 A fuse with a 2 A fuse.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????............................................................................................................................................................................................................................................................................................(Total for question = 7 marks)Q5.An electric kettle is connected to the 230 V mains supply.The power of the kettle is 960 W.(a)??(i)??A power of 960 watts is the same as(1)???A ?? 960 joules per coulomb???B ?? 960 joules per second???C ?? 960 newtons per metre???D ?? 960 newtons per second(ii)??State the equation linking power, current and voltage. (1)(iii)??Show that the current in the kettle is about 4 A.(2)(b)??The 960 W kettle is earthed and fitted with a fuse.(i)??Explain how this can protect the person using the kettle if there is a fault.(3)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... (ii)??Another kettle has twice as much power.It is connected to the same mains supply.Which of these fuse ratings should be used for this kettle?(1)???A ?? 1 A???B ?? 3 A???C ?? 5 A???D ?? 13 A(c)??A student has a pack of fuses labelled 2 A.Explain how she could use one of these fuses to check that the label is correct.You may draw a circuit diagram to help your answer.(3)..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(Total for question = 11 marks)?Q6.The photograph shows a worker fuelling an aircraft.Fuelling an electrically-charged aircraft can be dangerous.The worker connects a safety wire to the aircraft before adding the fuel.(a) Explain how an aircraft can become electrically charged while it is flying.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(b) Describe a possible danger of fuelling an electrically-charged aircraft.(1)??????..............................................................................................................................................??????..............................................................................................................................................(c) What electrical connection is made by the safety wire?(1)??????..............................................................................................................................................(d) Explain how connecting the safety wire reduces the possible dangers when fuellingan electrically-charged aircraft.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................?..............................................................................................................................................(Total for question = 6 marks)Q7.The graph shows how current and voltage vary for a filament lamp.(a) ?Draw a circuit diagram to show how you should connect the equipment needed to make the measurements needed to plot the graph.(4)(b) ?The resistance of the filament lamp changes as the voltage is increased.(i) ?How can you tell this from the graph?(1) ............................................................................................................................................. ............................................................................................................................................. (ii) ?Explain these changes in resistance.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 8 marks)Q8.A student investigates how the resistance of a wire depends on its length.The photograph shows the circuit that the student uses.(a) Draw a circuit diagram to show how the components in the photograph are connected.(3)(b) (i) Complete the table by naming the key variables in this investigation.(1)(ii) Describe the method the student should use for this investigation.(5)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(c) The table shows the student's measurements.(i) State the equation linking voltage, current and resistance.(1)(ii) Complete the table by calculating the missing value of resistance.(1)(d) (i) Use the results from the table opposite to plot a graph of resistance (y-axis)against length of wire (x-axis) and draw the line of best fit.(5)(ii) Write a conclusion for the investigation.(1)??????..............................................................................................................................................??????..............................................................................................................................................(iii) Explain how the graph supports this conclusion.(2)??????..............................................................................................................................................??????..............................................................................................................................................?????……………?..............................................................................................................................................(Total for question = 19 marks)Q9.(a) The diagram shows some electrical circuit symbols.(i) Which symbol represents a switch?(1)???A???B???C???D(ii) Which symbol represents a diode?(1)???A???B???C???D(b) A hairdryer connected to the mains supply takes a current of 5.5 A.(i) Which of these fuses should be used with the hairdryer?(1)???A ?? 3 A???B ?? 5 A???C ?? 7 A???D ?? 13 A(ii) Explain your answer.(1)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(iii) The hairdryer has a plastic case so there is no need for an earth wire connectionin the plug.Explain why the hairdryer is still safe to use.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????……………..............................................................................................................................................(Total for question = 6 marks)Q10.The diagram shows part of a lighting circuit in a house.The circuit is protected by fuse F.(a)??Give two reasons why the lamps are wired in parallel.(2)1 .......................................................................................................................................................................................................................................................................................2 ....................................................................................................................................................................................................................................................................................... (b)??What is the current at P? (1)???A ?? 0.17 A???B ?? 0.26 A???C ?? 0.43 A???D ?? 1.38 A(c)??Explain how the fuse protects the circuit.(3)..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(d)??(i)??State the equation linking power, current and voltage. (1)(ii)??Calculate the power of lamp L.[assume the mains voltage is 230 V](2)power = .............................................. W(iii)??Calculate the amount of energy transferred by lamp L in 3 minutes.Give the unit.(3)energy transferred = ...................... unit ......................(e)??This diagram shows another lighting circuit.(i)??Complete the table by putting a tick () in the box if the lamp is lit and a cross () in the box if the lamp is not lit.(2)(ii)??Suggest where this circuit would be useful in a house.(1).............................................................................................................................................Q11.This question is about static electricity.(a) Which of these materials is an electrical conductor?(1)???A ?? paper???B ?? plastic???C ?? silver???D ?? wood(b) A forensic scientist uses an electrostatic dust print lifter (EDPL) to take impressions offootprints.The diagram shows a simplified EDPL and a description of how it works.Use the idea of charge movement to explain how the lifting sheet becomesnegatively charged and the metal plate becomes positively charged.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(c) The photograph shows a typical dust print on a lifting sheet.Suggest why dust particles are lifted off the floor on to the lifting sheet.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(d) This photograph shows a charged polythene rod placed next to a stream of waterflowing from a tap.Suggest why the water is deflected.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????? (Total for question = 7 marks)Q12.The diagram shows an incomplete series circuit.(a)??(i)??Draw a thermistor to complete the circuit.(1)(ii)??Add a voltmeter to the circuit to measure the voltage across the lamp.(2)(b)??The voltmeter measures a voltage of 5.6 V.The ammeter measures a current of 790 mA.(i)??State the equation linking voltage, current and resistance.(1)(ii)??Calculate the resistance of the lamp.(3)resistance = ......................................................... Ω(c)??The completed circuit is moved from a cold room to a hot room.Explain how this would affect the brightness of the lamp.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (d)??State how the current in the circuit would change if another lamp is added in series with the first lamp.(1) ............................................................................................................................................. ............................................................................................................................................. (Total for question = 11 marks)?Q13.Identify the circuit diagram symbols.(a)??..............................................................................(b)??(1) ...................................................................................................................... (c)??(1) ...................................................................................................................... (d)??(1) ...................................................................................................................... (Total for question = 4 marks)?Q14.The photograph shows an electrical appliance called a toaster.(a)??The toaster has a power of 1800 W when operating at a voltage of 230 V.(i)??State the equation linking power, current and voltage.(1)(ii)??Show that the current in the toaster is about 8 A.(2)(iii)??Which fuse rating would be suitable for the toaster?(1)??A???? 1 A??B???? 3 A??C???? 7 A??D ????13 A(b)??The toaster uses mains electricity.Mains electricity provides alternating current.(i)??Describe the difference between alternating current (a.c.) and direct current (d.c.).(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii)??State a source of direct current.(1) ............................................................................................................................................. (Total for question = 7 marks)Q15.The graph shows how the current in a filament lamp varies as the voltage across it is change(a)??Draw a circuit diagram to show a circuit that could be used to make the measurements required to plot this graph.(b)??The resistance of the filament lamp changes as the voltage is increased.(i)??Determine how the resistance of the filament lamp changes as the voltage is increased.You should use data from the graph in your answer.(4) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii)??Explain why the resistance changes as the voltage is increased.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (c)??Draw a line on the graph to show how the current varies with voltage for a different filament lamp with a higher power rating.(1)(Total for question = 12 marks)?Q16.A thermistor is a device used in electric circuits.(a)??Which is the correct circuit symbol for a thermistor?(1)(b)??A student uses a thermistor as a device for measuring temperature.The student uses this apparatus to record how the resistance of the thermistor changes with temperature.He records the resistance of the thermistor every 5 °C as the water cools.The table shows some of his results.(i)??State the independent and dependent variables in his investigation.(2)independent variable.............................................................................................................................dependent variable……………………………………………………………………………………………..(ii)??Plot a graph of the student's results on the grid.(4)(iii)??Draw a curve of best fit.(1)(iv)?Use your graph to estimate the resistance of the thermistor when the temperature is 40 °C.(1)resistance = ........................................................... Ω(v)??Suggest three improvements for his investigation.(3)1 .......................................................................................................................................... ............................................................................................................................................. 2 .......................................................................................................................................... ............................................................................................................................................. 3 .......................................................................................................................................... ............................................................................................................................................. (c)??The thermistor is taken out of the water and connected in a series circuit with a 6.10 V cell.The resistance of the thermistor is 1060 Ω.(i)??State the equation linking voltage, current and resistance.(1)(ii)??Calculate the current in the circuit.(2)current = ........................................................... A(iii)??Explain what will happen to the current in the circuit when the temperature of the thermistor increases.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 18 marks)?Q17.The photograph shows solar cells on the roof of a house.(a)??State the energy transfer taking place in the solar cells.(2) ............................................................................................................................................. ............................................................................................................................................. (b)??The solar cells generate a current of 2.3 A.(i)??State the equation linking charge, current and time.(1)(ii)??Calculate the charge transferred by the solar cells in 15 seconds.(2)charge transferred = ........................................................... C(c)??The solar cells are wired in parallel.Suggest why the solar cells are not connected in series.(1) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 6 marks)?Q18.(a)??(i)??State the relationship between power, current and voltage.(1)(ii)??A lamp with a power of 6.5 W is connected to a 230 V supply.Calculate the current in the lamp.(3)current = ........................................................... A(b)??Three switches, S1, S2 and S3, are used to control a lamp in a large room.Each switch can be up or down, and each switch can turn the lamp on or off.When all three switches are up, the lamp is on.When all three switches are down, the lamp is plete the table by giving the missing information.(3)(Total for question = 7 marks)Q19.The passage is about static electricity.Use words from the box to complete the passage.Each word may be used once, more than once, or not at all.(4)A student combs her hair with a plastic comb. Her hair and the comb become charged.This happens because of the ................................between her hair and the comb. The comb becomes positively charged so her hair becomes.......................................charged.The student's hair sticks out because like charges .................................When the student moves the comb through her hair, she can hear a crackling sound.This is caused by .............................................transferring from the comb to her hair.(Total for question = 4 marks)?Q20.An adaptor plugged into the mains supply is used to charge a mobile phone.The photograph shows the adaptor that displays the voltage and current readings as the battery charges.(a)??(i)??State the equation linking voltage, current and resistance.(1)(ii)??Use the readings on the adaptor to calculate the resistance of the circuit used to charge the battery.Give the unit.(4) resistance = ..................... unit ..................... (b)??The battery of the mobile phone takes 45 minutes to charge.The charging current is 0.42 A.(i)??State the equation linking charge, current and time.(1)(ii)??Calculate the charge transferred to the battery.(2) (iii)??The cable connecting the mobile phone to the adaptor is changed for a much longercable of the same type.Explain how this would affect the time taken for the battery to charge.[assume same charge transferred to battery](3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ?(Total for question = 11 marks)?Q21.A student investigates the resistance of a thermistor.(a)??Which of these is the correct symbol for a thermistor(1)(b)??The student uses this apparatus to investigate how the resistance of a thermistor changes with temperature.(i)??Explain why the student places the thermistor in a beaker of water.(2)..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(ii)??The student also uses a voltmeter and an ammeter.How should the voltmeter and the ammeter be connected in his circuit?(1)(c)??The table shows the student's results.(i)??Plot a graph of these results on the grid.(4)(ii)??Circle the anomalous point on the graph.(1)(iii)??Draw a curve of best fit. (1)(d)??(i)??Why is the maximum temperature in the student's investigation limited to 100°C? (1)..........................................................................................................................................................................................................................................................................................(ii)??Suggest how the student obtains readings below room temperature.(1)..........................................................................................................................................................................................................................................................................................(Total for question = 12 marks)?Q22.This question is about an electric kettle.(a) The Sankey diagram represents the energy transfers taking place when the kettleheats some water.What is the efficiency of the kettle?(1)???A ?? 0.1???B ?? 0.9???C ?? 200???D ?? 1800(b) Why does the heating element in the kettle get hot when its electrical supply isswitched on?(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(c) The power of the heating element in the kettle is 2000 W when it is connected to a230 V mains supply.(i) State the equation linking power, current and voltage.(1)(ii) Show that the current in the heating element is approximately 9 A.(2)Current = ........................................................... A(iii) The plug of the kettle has a fuse.Fuses are available in values of1?A????????3?A????????7?A????????13?AIdentify the fuse that is the most suitable for this kettle, and explain why.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(Total for question = 8 marks)Q23.This question is about electric charge.(a)??When a balloon is rubbed with a cloth, the balloon becomes negatively charged.Tick () the two correct statements in the table.(2)(b)??When petrol passes through a delivery pipe, electrostatic charge can build up as shown in the diagram.(i)??Give a reason why a build-up of charge can be dangerous.(1) ............................................................................................................................................. ............................................................................................................................................. (ii)??State how the build-up of electrostatic charge can be prevented.(1) ............................................................................................................................................. ............................................................................................................................................. (c)??The diagram shows coffee granules passing through a funnel into a container.As the granules pass through the funnel, they gain an electrostatic charge and spread out as they fall.Explain, in terms of charges, why the granules spread out.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 6 marks)?Q24.A student holds a roll of sticky tape and pulls the end down as shown in the diagram.This causes both the roll and the end of the tape to become electrically charged by friction.(a)??Explain how an object becomes charged by friction.(3)........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)??The student lets go of the end of the tape and the charges cause it to move towards the roll.Explain why the end of the tape moves back towards the roll.(2)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(Total for question = 5 marks)?Q25.(a)??The table shows the names and circuit symbols of some electrical plete the table by giving the missing information.(4)(b)??A student wants to find the resistance of a fixed resistor.She measures a current of 0.50 A in the resistor when the voltage across it is 8.0 V.(i)??State the equation linking voltage, current and resistance.(1)(ii)??Calculate the resistance of the resistor.(2)resistance = ........................................................... Ω(c)??The student replaces the fixed resistor with a light dependent resistor (LDR) and measures its resistance at different light intensities.Sketch a graph of the expected results.(3)?(Total for question = 10 marks)?Q26.This question is about electrical components.(a)??Draw a straight line from each electrical component to its correct symbol.One has been done for you.(3)(b)??(i)??Name an electrical component whose resistance decreases when it is moved into brighter light.(1) ............................................................................................................................................. (ii)??Name an electrical component whose resistance decreases as its temperature increases.(1) ............................................................................................................................................. (Total for question = 5 marks)Q27.This question is about electrostatic charges.(a) Complete the sentences using words from the box.Each word may be used once, more than once or not at all.(2)When a plastic rod is rubbed with a cloth, the plastic rod gains ..........................After the plastic rod has been rubbed with the cloth, the plastic rod has a...................................... charge.(b) Electrostatic charges can be useful during paint spraying.(i) The droplets of paint are given the same charge as they leave the sprayer.Explain why this is an advantage.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(ii) The droplets of paint are positively charged.The object being painted is given a negative charge.Explain why this is an advantage.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(c) Give one hazard caused by electrostatic charges and state how the risk from this hazard can be reduced.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(Total for question = 8 marks)Q28.A man pushes a metal trolley along a corridor towards a lift. The trolley has nylon wheels and the floor of the corridor is covered with plastic. The man wears shoes with rubber soles.As he moves the trolley, the man gains an electric charge. (a)??Explain how the man gains an electric charge.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (b)??The man presses a metal button to operate the lift.There is a spark and the man receives an electric shock. The spark lasts for 75ms and 0.0017C of charge passes. (i)??State the equation linking charge, current and time.(1)(ii)??Calculate the average current in the spark.Give the unit.(3) current = .............................. unit .............................. (c)??Metal appliances, such as the lift button, are earthed for safety.Explain why the man receives a shock even though the button is properly earthed.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 9 marks)Q29.When a plastic rod is rubbed with a cloth, the rod gains charge.(a) ?How could you show that the plastic rod gains charge?(1) ............................................................................................................................................. ............................................................................................................................................. (b) ?Explain how the plastic rod gains charge when it is rubbed.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (c) ?There are two types of charge.Describe how you could demonstrate this using different insulating rods and a cloth.In your answer, you should name any other equipment you would use.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 6 marks)Q30.A wind turbine generates electricity for the National Grid.(a) The useful energy transfer in the wind turbine is(1)???A ?? chemical energy to electrical energy???B ?? gravitational potential energy to electrical energy???C ?? kinetic energy to electrical energy???D ?? sound energy to electrical energy(b) The generator in the wind turbine transfers 39 MJ of energy in 1 minute.The generator current is 490 A.(i) Calculate the output voltage of the generator.(3)Voltage = ........................................................... V The generator provides a direct current (d.c.).This d.c. is changed to an alternating current (a.c.).The frequency of the alternating current is 50 Hz.(i) Explain the meaning of 50 Hz alternating current.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................Q31.A student plans to measure the resistance of a piece of wire.He sets up this circuit and finds that it does not work.(a)??Identify the three errors in the student's circuit.(3)1 ............................................................................................................................................. ............................................................................................................................................. 2 ............................................................................................................................................. ............................................................................................................................................. 3............................................................................................................................................. ............................................................................................................................................. (b)??The student uses a correct circuit to obtain these results.(i)??Plot a graph to show the relationship between current and voltage for the wire. (5)(ii)??Find the current when the voltage is 2.5 V.(1) ............................................................................................................................................. (iii)??Suggest why the line on the graph curves.(1) ............................................................................................................................................. ............................................................................................................................................. (iv)?Describe what else the student should do to find an accurate value for the ????????resistance of the piece of wire at a constant temperature.(4) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 14 marksQ32.The resistance of a Light Dependent Resistor (LDR) is affected by the amount of light that shines on It.A student investigates this relationship using the circuit shown.(a)??(i)??The student uses a voltmeter to measure the voltage across the LDR.Add this voltmeter to the circuit diagram.(2)(ii)??Explain how the student can work out the resistance of the LDR using this circuit.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (b)??The student shines light on the LDR through a circular hole in a piece of black card, as shown in the diagram.The student repeats the experiment using cards with holes of different diameter. The distance from the card to the LDR is always 5 cm. The student varies the current in the circuit by adjusting the variable resistor.(i)??The independent variable in this experiment is(1)???A ?? the brightness of the light source???B ?? the diameter of the hole???C ?? the distance from the card to the LDR???D ?? the resistance of the LDR(ii)??A controlled variable in this experiment is(1)???A ?? the current in the circuit???B ?? the diameter of the hole???C ?? the distance from the card to the LDR???D ?? the resistance of the LDR(iii)??The photograph shows how the student places a metal ruler to measure the diameter of one of the holes.Suggest how the student can improve this technique while still using the same ruler.(1) ............................................................................................................................................. ............................................................................................................................................. (c)??The table shows the student's results.(i)??Plot the student's results on the grid.(4)(ii)??Draw a curve of best fit on the graph.(1)(iii)??Describe the relationship between the resistance of the LDR and the diameter of the hole.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 14 marks)?Q33.An electric vehicle has a rechargeable battery.The battery is recharged by connecting it to a charging station.(a)??The battery voltage is 385 V.(i)??State the amount of energy transferred when one coulomb of charge passes through a potential difference of 385 V.(1)energy transferred = ............................................ J(ii)??Show that, when a charge of 180000 C passes through the battery, the total amount of energy transferred to the battery is about 70 MJ.(2)(iii)??During the charging process, energy is also transferred to the charging station from the mains supply.Explain why the amount of energy transferred from the mains supply is more than 70 MJ.(2)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(b)??Charging takes 110 minutes and causes a total charge of 180000 C to pass through the battery.(i)??State the equation linking charge, current and time.(1)(ii)??Calculate the average charging current in the battery.(3)current = ............................................ A(Total for question = 9 marks)Q34.A student investigates how to produce a voltage.He hangs a magnet from a spring, above a coil that is connected to a data logger.(a)??The student pulls the magnet through the coil to X and then releases it.The magnet moves up and down through the coil.The data logger produces this graph of voltage against time.(i)?? Explain why the data logger records a varying voltage.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii)?? Which feature of the graph shows that the voltage is alternating?(1) ............................................................................................................................................. ............................................................................................................................................. (iii)?? Suggest why the voltage changes as shown by the graph.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (b)??The student repeats the experiment using two magnets taped pared to one magnet, these two magnets take a longer time to move up and down.The dotted line on the grid shows the original graph for one magnet.On the same grid, sketch the graph that would be produced using two magnets.(3)(Total for question = 8 marks)Q35.The photograph shows a fuel delivery at a petrol station.(a)?? Explain how a fuel tanker can become electrically charged while it is moving.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (b)?? Pumping fuel from an electrically-charged tanker can be dangerous.(i)?? Describe a possible danger of pumping fuel from an electrically-charged tanker.(1) ............................................................................................................................................. ............................................................................................................................................. (ii)?? The driver connects an earth wire to the fuel tanker before pumping fuel.Explain how connecting the earth wire reduces the possible dangers.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 5 marks)Q36.Mains electricity is used in circuits at home.(a)??Double insulation is needed for safety when there is(1)??? ???A ?? no circuit breaker??? ???B ?? no earth connection??? ???C ?? no fuse??? ???D ?? no switch(b)??A fuse is used so that(1)??? ???A ?? an earth connection is not needed??? ???B ?? the appliances are more efficient??? ???C ?? the circuit cannot overheat if there is a fault??? ???D ?? the user cannot touch a live wire(c)??Most lamps at home have their own switch.This is because the lamps are connected(1)??? ???A ?? in parallel??? ???B ?? in series??? ???C ?? to a fuse??? ???D ?? to an earth wire(Total for question = 3 marks)Q37.A car becomes electrically charged as it travels along a road.(a)??(i)??Explain how a moving car becomes electrically charged.(2)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(ii)??Why does this charge remain on the car after it has stopped moving?(1)..........................................................................................................................................................................................................................................................................................(b)??Some people prefer to prevent their car from becoming charged.They do this by fixing a metal strap underneath the car.The metal strap rubs on the ground as the car moves.(i)??Suggest why it is safer to have no electrical charge on a car.(1).......................................................................................................................................................................................................................................................................................... (ii)??Explain how the metal strap prevents a car from becoming charged.(2)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(Total for question = 6 marks)?Q38.A student investigates how the current in a filament lamp varies as the voltage across it changes.(a)??Draw a suitable circuit diagram for this investigation.(3)(b)??Describe a method the student could use for this investigation.(4) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ?(Total for question = 7 marks)?Q39.A student investigates how the length of a piece of wire affects its resistance.(a)??The photograph shows how he uses a ruler to measure the length of the wire.(i)??State how the student could improve the precision of his measurement.(1) ............................................................................................................................................. ............................................................................................................................................. (ii)??Suggest three ways the student could improve the accuracy of his measurement.(3)1 .......................................................................................................................................... 2 .......................................................................................................................................... 3 .......................................................................................................................................... (b)??The student finds the resistance for seven different lengths of wire.He does this by passing a small current through each wire.(i)??Explain why the current in each wire must be small.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii)??The table shows the student's results.Suggest two improvements the student could make to the data he collects.(2)1 .......................................................................................................................................... ............................................................................................................................................. 2 .......................................................................................................................................... ............................................................................................................................................. (iii)??Plot a graph of the student's results on the grid.(4)(iv)?Draw the line of best fit.(1)(v)??Describe the relationship shown by the graph.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 15 marks)?Q40.A student investigates how the resistance of a piece of wire changes with voltageacross the wire.The student connects an ammeter, a voltmeter, a battery, a variable resistor and thewire in an electrical circuit.(a) (i) Complete the diagram to show how the student should connect the circuit.(3)(ii) Describe what she should do to obtain a set of results for her investigation.(3)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(b) The student keeps the temperature of the wire constant during the investigation.(i) Suggest why she does this.(1)??????..............................................................................................................................................??????..............................................................................................................................................(ii) Suggest how she does this.(1)??????..............................................................................................................................................??????..............................................................................................................................................(c) When the student looks at her results, she notices that the voltage across the wireis directly proportional to the current in it.(i) State the relationship linking voltage, current and resistance.(1)(ii) The student calculates the resistance and then plots a graph of resistanceagainst voltage.On the axes, sketch the shape of her graph.(1)(Total for question = 10 marks)Q42.The diagram shows some lamps connected together.There are 20 small lamps connected in series with a 9 V supply.(a) (i) What is the voltage across each lamp in the series circuit?(1)??????..............................................................................................................................................(ii) Each lamp has a power of 1.5 W.State the equation linking power, current and voltage.(1)(iii) Show that the current in the circuit is about 3 A.(2)(b) (i) The lamps are on for 7 hours a day for 5 days.Calculate the total energy transferred during this time.(3)(ii) Describe the energy changes that take place in the lamps when they are connected to the power supply.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................? (Total for question = 9 marks)Q43.The diagram shows a lighting circuit in a house.(a)??(i)??Component X is(1)???A ?? a double insulated wire???B ?? an earth connection???C ?? a fuse???D ?? a switch(ii)??The lamps are connected in parallel.State an advantage of using a parallel circuit for lighting.(1)..........................................................................................................................................................................................................................................................................................(b)??The lighting circuit is connected to a mains supply that provides an alternating current.Explain what is meant by an alternating current.You may draw a diagram to help your answer.(2)....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(c)??Lamp Y is removed and replaced with a low-energy lamp.When the low-energy lamp is connected to a 230 V supply, the current in it is 0.12 A.(i)??Calculate the amount of energy transferred by the low-energy lamp in 7 hours.(3)energy transferred = .................................... J(ii)??The low-energy lamp gives the same amount of light as lamp Y, but uses much less power.Which row of the table compares the low-energy lamp correctly to lamp Y?(1)(Total for question = 8 marks)?Q44.A student is given an unknown electrical component, X.He uses a circuit to investigate how the current in X varies with the voltage across it. (a)??Which of these circuits is correct for his investigation?(1)(b)??The table shows the student's results.(i)??Plot a graph of these results and draw a curve of best fit.(4)(ii)??State the equation linking voltage, current and resistance.(1)(iii)??Calculate the resistance of component X when the voltage across it is 10.0 V.Give the unit.(4) resistance = ............................... unit ............................... (iv)??Describe the pattern shown by this graph.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (v)??Suggest a conclusion for the investigation.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 15 marks)?Q45.The table shows information about three electrical appliances.(a)??(i)??State the relationship between power, current and voltage.(1)(ii)??Calculate the current in the television.[assume that the mains voltage is 230 V](2) current = ........................................................... A (b)??The photographs show the different cables used for the clothes iron and the lamp.(i)??Suggest why the wires in the clothes iron cable are thicker than the wires in the lamp cable.(1) ............................................................................................................................................. ............................................................................................................................................. (ii)??The clothes iron cable has three wires, E, N and L.Which of these wires is connected to the fuse?(1) ............................................................................................................................................. (iii)??Suggest why the lamp is safe to use, even though its cable only has two wires.(1) ............................................................................................................................................. ............................................................................................................................................. (c)??The lamp is switched on for 55 minutes.Calculate the energy transferred by the lamp in this time.(3) energy transferred = ........................................................... J (Total for question = 9 marks)?Q46.The photograph shows an electric heater.(a) ?The power of the heater is 2000 W.The heater is connected to a 230 V mains supply.(i) ?State the equation linking power, current and voltage.(1)(ii) ?Calculate the current in the heater.(2)current = ........................................................... A(iii) ?Which of these fuses should be used with the heater?(1)???A ?? 1A???B ?? 5A???C ?? 7A???D ?? 13A(b) ?The two heating elements can be connected in series or in parallel.Describe an advantage of each method. (2)series............................................................................................................................................ ............................................................................................................................................. parallel............................................................................................................................................ ............................................................................................................................................. (c) ?Some electrical appliances are fitted with an earth wire.(i) ?Describe how an earth wire acts as a safety feature.(4) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii) ?Explain why this heater should be fitted with an earth wire.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 12 marks)Q47.A soldering iron is a tool used when joining electronic components in a circuit.It has an electric heater.(a) Soldering iron A operates when connected to the mains supply.Soldering iron A is labelled 230 V, 30 W.(i) What does 30 W tell you about the energy transfer in the soldering iron?(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(ii) This soldering iron has an earth connection.Explain how an earth connection protects the user.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(b) Soldering iron B is connected to a low voltage power supply.Soldering iron B is labelled 24 V, 70 W.A student says:(i) Use information from the soldering iron labels to evaluate this statement.(3)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(ii) There is a step-down transformer in the power supply for soldering iron B.Describe the structure of a step-down transformer.You may draw a labelled diagram to help your answer.(3)?..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................????……………...............................................................................................................................................(Total for question = 10 marks)Q48.A filament lamp is connected to a battery.The lamp is switched on and a data logger records the current.The graph shows the results from the data logger.(a)??Describe in detail how the current varies with time.Refer to data from the graph in your answer.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (b)??The battery has a voltage of 12 V.The lamp reaches its normal operating temperature after a short while.(i)??State the current in the lamp when it is at its normal operating temperature.(1)current = ........................................................... A(ii)??State the relationship between voltage, current and resistance.(1)(iii)??Calculate the resistance of the lamp at its normal operating temperature.Give the unit.(4)resistance = ........................................ unit ........................................ (iv)?State the relationship between power, current and voltage.(1)(v)??Calculate the power of the lamp at its normal operating temperature.(2)power = ........................................................... W(c)??Suggest why a filament lamp is most likely to fail when it is first switched on.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (Total for question = 14 marks)?Q49.The photograph shows an extension cable on a reel.There is a warning label on the reel.(a) ?(i) ?State the equation linking power, current and voltage.(1)(ii) ?Complete the table by inserting the missing value.(1)(b) ?The extension cable is fitted with a 13 A fuse.(i) ?Describe how the fuse protects the cable.(3) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii) ?Explain why a 5 A fuse is not suitable for this extension cable.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (iii) ?Suggest why the maximum recommended current is lower when the cable is coiled up.(1) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ? (Total for Question = 8 marks)Q50.The photograph shows a solar-powered battery charger connected to a mobile phone.When the battery charger is used, it transfers light energy from the Sun to the battery of the mobile phone.(a) ?Complete the energy transfer diagram.(2)(b) ?It takes 3.5 hours to recharge the battery fully.The average current supplied by the charger is 400 mA.(i) ?State the equation linking charge, current and time.(1)(ii) ?Calculate the amount of charge needed to recharge the battery fully, and give the unit.(3)charge = ........................................................... unit ...........................................................(c) ?If the charger is moved into the shade, the output power decreases.The voltage across the charger stays the same.Explain how moving the charger into the shade affects the time needed to recharge the battery fully.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ? (Total for Question = 8 marks)Q51.A student investigates how the resistance of a thermistor varies with temperature.(a) Draw the circuit symbol for a thermistor.(1)(b) The student uses voltmeter and ammeter readings to find the resistance at eachtemperature.One set of readings is shown below.(i) State the equation linking voltage, current and resistance.(1)(ii) Show that the resistance of the thermistor at 80 °C is about 5000 Ω.(3)(c) Another student takes measurements for two more components, A and B.The graphs show the pare the results for component A and component B.(5)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????.............................................................................................................................................. (Total for question = 10 marks)Q52.A student sets up a circuit to investigate how the current in different components varies with voltage.He investigates these components.???a short thick copper wire???a filament lamp???a long thin copper wire???a diode(a)??State four other pieces of equipment the student needs.(4) 1 .......................................................................................................................................... 2 .......................................................................................................................................... 3 .......................................................................................................................................... 4 .......................................................................................................................................... (b)??During the investigation, the student keeps the two copper wires at a constant temperature.(i)??Give a reason why he should keep the wires at a constant temperature.(1) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (ii)??Describe how he could keep the wires at a constant temperature.(2) ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. ............................................................................................................................................. (c)??The student obtains a graph for each component.Draw a straight line linking each component to its correct graph.(3)?(Total for question = 10 marks)?Q53.A light dependent resistor (LDR) can be used as a sensor to detect light intensity.Describe how the resistance of an LDR varies as the light intensity changes.You may sketch a graph to help your answer.(3)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????.............................................................................................................................................. (Total for question = 3 marks)Q54.The diagram shows a heater coil and a resistor connected to a 12 V battery and an ammeter.The ammeter reading is 1.2 A.(a) (i) State the equation linking voltage, current and resistance.(1)(ii) Calculate the voltage across the 4.0 Ω resistor.(2)Voltage = ........................................................... V(iii) Show that the voltage across the heater coil is about 7 V.(2)(iv)Calculate the energy transferred to the heater coil in 5.0 minutes.(3)Energy transferred = ........................................................... J(v) At first, the temperature of the water increases.After a while, the temperature reaches a steady value below the boiling point of water.Explain why the temperature reaches a steady value.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................(b) Resistors can be used as heating elements in the rear windows of cars.The diagram shows two possible designs.(i) Complete the table by placing a tick in the correct boxes.(1)(ii) Describe the advantages and disadvantages of design X when used as aheater in a car window.(3)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................?????……………?..............................................................................................................................................(Total for question = 14 marks)Q55.A student investigates how the resistance of a thermistor changes with temperature.He measures a current and a voltage.The diagram shows part of the circuit that the student uses.(a) (i) Label the thermistor on the diagram.(1)(ii) Add to the diagram to show how a voltmeter should be connected.(2)(b) The student varies the temperature of the thermistor and obtains the results below.(i) State the equation linking voltage, current and resistance.(1(ii) The voltage across the thermistor is 12 V.Calculate the resistance of the thermistor at 20 °C.(2)Resistance = ........................................................... Ω(iii) Use the results from the table opposite to plot a graph of current againsttemperature.(5)(iv)Use your graph to describe how the current in the thermistor changes as thetemperature increases.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????.............................................................................................................................................. (v) The student concludes:Evaluate this conclusion.(2)??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????..............................................................................................................................................??????……………..............................................................................................................................................(Total for question = 15 marks)Q56.(a)??The diagram shows part of an electric plete the circuit diagram by adding???a resistor in series with the lamp and battery???a second lamp in parallel with the first lamp???a voltmeter that measures the voltage across the resistor???an ammeter that measures the current in the resistor(4)(b)??The current in a resistor is measured for different voltages.The table shows the results.(i)??Plot a graph of this data on the grid.(4)(ii)??Circle the anomalous point on the graph.(1)(iii)??Draw a line of best fit. (1)(iv)State the equation linking voltage, current and resistance.(1)(v)??Use your graph to find a value for the resistance of the resistor.(2)resistance ........................................................... Ω ................
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