CHAPTER 1 (Introduction to electron theory)



Chapter 1 (power source)

14. Active materials of a lead acid cell are

a. lead peroxide

b. sponge lead

c. dilute sulphuric acid

d. all the above

15. The capacity of a cell measured in

a. watt hour

b. watts

c. amperes

d. amperes hours

16. The capacitive of a lead acid cell does not depends on its

a. rate of change

b. rate of discharge

c. temperature

d. quantity of active martial

17. Which of the following is a dry but rechargeable cell

a. nickel –cadmium cell

b. mercury cell

c. lead acid cell

d. solar cell

18. Rating of a battery is usually expressed in

a. watt-hour

b. joule

c. ampere hour

d. amperes

19. The current delivering capacity of a cell depends on

a. condition of the electrolyte

b. quality of the electrolyte

c. physical size of the electrode

d. all the above

20. Which of the following is a dry but rechargeable cell

a. nickel cadmium cell

b. mercury cell

c. lead acid cell

d. solar cell

21. A dead storage battery cab be revived by

a. a dose of H2SO4

b. adding so called battery restorer

c. adding distilled water

d. none of the above

Chapter 2 (Electrical circuit)

22. If, in Fig. 1.99, resistor Rz becomes open circuited the reading of the voltmeter will become

a. zero

b. 150V

c. 50 V

d. 200 V

[pic]

23. What ever the battery voltage in Fig. below ,it is certain that smallest current will flow in the resistance of ohm.

a. 300

b. 500

c. 200

d. 100

[pic]

24. Which of the following statement is TRUE both for a series and a parallel d.c. circuit?

a. powers are additive

b. voltages are additive

c. currents are additive

d. elements have individual currents

25. The positive terminal of a 6-V battery is connected to the negative terminal of a l2-V battery whose positive terminal is grounded. The potential at the negative terminal of the 6-V battery is-volt.

a. +18

b. -12

c. - 12

d. + 12

26. In the above question, the potential at the positive terminal of the 6-Vbattery is volt.

a. +6

b. -6

c. - 12

d. + 12

27. A 100-W, llO-V and a 50-W, 1l0-V, l amps are connected in series across a 220-V d.c. source. If the resistance of the two lamps is assumed to remain constant, the voltage across the 1000Wlamp is volt.

a. 110

b. 73.3

c. 146.7

d. 220

28. In the parallel circuit of Fig. below, the value of Vo is volt.

a. 12

b. 24

c. 0

d. - 12

[pic]

29. In the series circuit of Fig. given below, the value of Vo is volt.

a. 12

b. - 12

c. 0

d. 6

[pic]

30. In Fig. 1.103, there is a drop of 20 V on each resistor. The potential of point A would be ____ volt.

a. + 80

b. - 40

c. + 40

d. - 80

[pic]

31. From the voltmeter reading of Fig. given below it is obvious that

a. 3 Q resistor is short-circuited

b. 6 Q resistor is short-circuited

c. nothing is wrong with the circuit

d. 3 Q resistor is open-circuited

[pic]

32. With reference to Fig. given below which of the following statement is true?

a. E and R( fonn a series circuit

b. R( is in series with R3

c. R ( is in series with R3

d. there is no series circuit

[pic]

33. Which of the following statements is correct concerning the circuit of Fig. below.

a. R2 and R3 fonn a series path

b. E is in series with RI

c. R. is in parallel with R3

d. RI' R2 and R3 fonn a series circuit.

[pic]

34. What is the equivalent resistance in ohms between points A and B of Fig. below? All resistances are in ohms.

a. 12

b. 14.4

c. 22

d. 2

35. When checked with an ohmmeter, an ‘open’ resistor reads

a. infinite

b. zero

c. low but not zero

d. high but not infinite

36. While measuring resistance with an ohmmeter one should not touch test leads because

a. of the possibility of electric shock

b. it may lower the ohmmeter readings

c. it may ground the resistor

d. it may short the resistor being checked

37. If a 220V heater is used on 110V supply, heat produced by it will be _____ as much

a. one half

b. twice

c. one-fourth

d. four times

38. For a given line voltage, four heating coils will produce maximum heat when connected

a. all in parallel

b. all in series

c. with two parallel pairs in series

d. one pair in parallel with the other two in series

39. One kWh of energy equals nearly

a. 1000w

b. 860kcal

c. 4186j

d. 735.5w

Chapter 4( Network theorems)

40. Kirchoff’s current law is applicable to only

a. closed loops in a network

b. electronic circuits

c. junctions in a network

d. electric circuits.

41. Kirchoff’s voltage law is concerned with

a. IR drops

b. battery e.m.f.’s

c. junction voltages

d. both (a) and (b)

42. According to KVL, the algebraic sum of all IR drops and e.m.f.s in any closed loop of a network is always

a. zero

b. positive

c. negative

d. determined by battery e.m.f.’s

43. The algebraic sign ~f an IR drop is primarily dependent upon the

a. amount of current flowing through it

b. value of R

c. direction of current flow

d. battery connection.

44. Maxwell's loop current method of solving electrical networks

a. uses branch currents

b. utilizes Kirchoff’s voltage law

c. is confined to single-loop circuits

d. is a network reduction method.

45. Point out of the WRONG statement. In the node-voltage technique of solving networks, choice of a reference node does not

a. affect the operation of the circuit

b. change the voltage across any element

c. alter the p.d. between any pair of nodes

d. affect the voltages of various nodes.

46. The nodal analysis is primarily based on the application of

a. KVL

b. KCL

c. Ohm's law

d. both (b) and (c)

e. both (a) and (b).

47. Superposition theorem can be applied only to circuits having elements.

a. non-linear

b. passive

c. linear bilateral

d. resistive

48. The Superposition theorem is essentially based on the concept of

a. duality

b. linearity

c. reciprocity

d. non-linearity

49. While Thevenining a circuit between two terminals, Vth equals

a. short-circuit terminal voltage

b. open-circuit terminal voltage

c. EMF of the battery nearest to the termnals

d. net voltage available in the circuit.

50. Thevenin resistance Rth is found

a. between any two 'open' terminals

b. by short-circuiting the given two terminals

c. by removing voltage sources along with their internal resistances

d. between same open terminal as for Vth.

51. While calculating Rth' constant-current sources in the circuit are:

a. replaced by 'opens'

b. replaced by 'shorts'

c. treated in parallel with other voltage sources

d. converted into equivalent voltage sources.

52. Thevenin resistance of the circuit of Fig. below is

a. 6

b. 3

c. 9

d. 2

[pic]

53. The load resistance needed to extract maximum power from the circuit

a. 2

b. 9

c. 6

d. 18

[pic]

54. The Norton equivalent of a circuit consists of a 2 A current sources in parallel with a 4Ω resistor. Thevenin equivalent of this circuit is a-volt source in series with a 4Ω resistor.

a. 2

b. 0.5

c. 6

d. 8

55. If two identical 3 A, 4Ω Norton equivalent circuits are connected in parallel with like polarity to like the combined Norton equivalent circuit is

a. 6 Ω, 4Ω

b. 6A, 2 Ω

c. 3 A, 2 Ω

d. 6 A, 8 Ω

56. Two 6 V, 2 Ω batteries are connected in series siding. This combination can be replaced by a single equivalent current generator of _____with a parallel resistance of ____ohm

a. 3 A, 4 Ω

b. 3 A, 2 Ω

c. 3 A, 1 Ω

d. 6 A, 2 Ω

57. Two identical 3-A, 1 Ω batteries are connected in parallel with like polarity to like. The Norton equivalent circuit of this combination is

a. 3 A, 0.5 Ω

b. 6A, l Ω

c. 3 A, 1Q

d. 6 A, 0.5 Q

58. For a linear network containing generators and impedances, the ratio of the voltage to the current produced in other loop is the same as the ratio of voltage and current obtained when the positions of the voltage source and the ammeter measuring the current are interchanged. This network theorem is known as-theorem.

a. Millman's

b. Norton's

c. Tellegen's

d. Reciprocity

59. A 12 volt source will an internal resistance of 1.2ohms is connected across a wire-would resistor. Maximum power will be dissipated in the resistor when its resistance is equal to

a. zero

b. 1.2 ohm

c. 12 ohm

d. infinity

Chapter 5 (electrostatics and capacitance)

60. In the SI system of units, the unit of force is

a. kg-wt

b. Newton

c. joule

d. N-m

61. The basic unit of electric charge is

a. ampere-hour

b. watt-hour 8. One kWh of energy equals nearly

c. coulomb

d. farad

62. The SI unit of energy is

a. joule

b. kWh

c. kcal

d. m-kg

63. According to the commonly used sign convention for voltages

a. a fall in voltages is considered positive

b. a raise in voltages is considered positive

c. IR drop is taken as negative

d. Battery EMF’S are taken as positive

64. The algebraic sign of an IR drop is primarily dependent upon the

a. amount of current flowing through it

b. value of R

c. direction of current flowing through it

d. battery connection

65. While applying Kirchoff’s laws to electronics circuits, assumed direction of current flow must be

a. clockwise

b. from left to right

c. anticlockwise

d. either (a) or(b)

66. Superposition theorem can be applied only to circuit having ______ element

a. Non –linear

b. passive

c. linear bilateral

d. resistive

67. The Superposition theorem is essentially based on the concept of

a. duality

b. linearity

c. reciprocity

d. non- linearity

68. While Theveninizing a circuit between two terminals VTH equals

a. short circuit terminal voltage

b. open circuit terminal voltage

c. emf of the battery nearest to the terminals

d. net voltage available in the circuit

69. Thevenin resitance Rth is found

a. between any two ‘open’ terminals

b. by short-circuiting the given two terminals

c. by removing voltage sources along with their internal resistances.

d. between same open terminals as for Vth

70. Norton’s equivalent of a circuit consists of a

a. constant current source with a conductance in parallel

b. constant current source in series with an infinite resistance

c. constant voltage source in parallel with a high resistance

d. single current source and a single voltage source.

71. While calculating Rth constant current source in the circuit are

a. replaced by ‘opens’

b. replaced by ‘shorts’

c. treated in parallel with other voltage sources

d. converted into equivalent voltage sources.

72. The Norton equivalent of a circuit consists of a 2A current source in parallel with a 4Ω resistor. Thevenin equivalent of this circuit is a _______ volt source in series with a 4Ω resistor.

a. 2

b. 0.5

c. 6

d. 8

73. If 2 identical 3A, 4Ω Norton equivalent circuits are connected in parallel with like polarity to like, the combined Norton equivalent circuit is

a. 6A, 4Ω

b. 6A, 2Ω

c. 3A, 2Ω

d. 6A, 8Ω

74. For abstracting maximum power from any two given terminals of a circuit, the load resistance across the terminal should be

a. Four times the internal resistance of the network

b. Equal to the circuit resistance when viewed back from the two terminals

c. Less than the circuit resistance

d. Greater than the circuit resistance

75. If the current through a resistor is halved, wattage developed by it would be

a. Halved

b. quadrupled

c. cut to one fourth

d. doubled

76. When checked with an ohmmeter, an ‘open’ resistor reads

a. infinite

b. zero

c. low but not zero

d. high but not infinite

77. While measuring resistance with an ohmmeter one should not touch test leads because

a. of the possibility of electric shock

b. it may lower the ohmmeter readings

c. it may ground the resistor

d. it may short the resistor being checked

78. An ideal voltage source has

a. Zero internal resistance

b. Infinite internal resistance

c. A load –dependent voltage

d. a load dependent current

79. A real voltage source has

a. Zero internal resistance

b. Infinite internal resistance

c. A small internal resistance

d. A large internal resistance

80. An ideal current source has

a. Zero internal resistance

b. Infinite internal resistance

c. A load – dependent voltage

d. A load – dependent current

81. A real current source has

a. Zero internal resistance

b. Infinite internal resistance

c. A small internal resistance

d. A large internal resistance

82. The Thevenin voltage is the same as the

a. Shorted –load voltage

b. I deal source voltage

c. Open –load voltage

d. Norton voltage

83. The Thevenin resistance is equal in value to the

a. Load resistance

b. Half the load resistance

c. Internal resistance of a Norton circuit

d. open load resistance

84. To get the Thevenin voltage , you have to

a. short the load resistor

b. open the load resistor

c. short the voltage source

d. open the voltage source

85. To get the Norton current, you have to

a. short the load resistor

b. open the load resistor

c. short the voltage source

d. open the voltage source

86. Norton current is sometime called the

a. shorted – load current

b. open load current

c. Thevenin current

d. Thevenin voltage

87. An open resistor has

a. Infinite current through it

b. zero voltage across it

c. Infinite voltage across it

d. Zero current through it

88. A shorted resistor has

a. Infinite current through it

b. zero voltage across it

c. Infinite voltage across it

d. Zero current through it

89. The voltage out of an ideal voltage source

a. is zero

b. is constant

c. depends on the value of load resistance

d. depends on the internal resistance

90. The current out of an ideal current source

a. is zero

b. is constant

c. depends on the value of load resistance

d. depends on the internal resistance

91. Thevenins theorem replaces a complicated circuit facing a load by an

a. Ideal voltage source and parallel resistor

b. Ideal current source and parallel resistor

c. Ideal voltage source and series resistor

d. Ideal current source and series resistor

92. Norton’s theorem replaces a complicated circuit facing a load by an

a. Ideal voltage source and parallel resistor

b. Ideal current source and parallel resistor

c. Ideal voltage source and series resistor

d. Ideal current source and series resistor

Chapter 5(Electrostatics and capacitance)

93. The capacitance of a capacitor is not influenced by

a. plate thickness

b. plate area

c. plate separation

d. nature of the dielectric

94. Any charge given to the battery when taken off the vehicle is called

a. bench charge

b. step charge

c. float charge

d. trickle charge

95. In the SI system of units, the unit of force is

a. kg-wt

b. Newton

c. joule

d. N-m

96. The basic unit of electric charge is

a. ampere-hour

b. watt-hour 8. One kWh of energy equals nearly

c. coulomb

d. farad

97. The SI unit of energy is

a. joule

b. kWh

c. kcal

d. m-kg

98. The unit of absolute permittivity of a medium is

a. joule/coulomb

b. newton-metre

c. farad/metere

d. farad/coulomb

99. If relative permittivity of mica is 5, its absolute permittivity is

a. 5εo

b. 5/ εo

c. εo/ 5

d. 8.854 × 10-12

100. The unit of electric intensity is

a. joule/coulomb

b. newton/coulomb

c. volt/metre

d. both (b) and (c)

101. Which of the following .is zero inside a charged conducting sphere ?

a. potential

b. electric intensity

c. both (a) and (b)

d. both (b) and (c)

102. Inside a conducting sphere, ____ remains constant every day

a. electric flux

b. electric intensity

c. charge

d. potential

103. A capacitor consists of two

a. insulation separated by a dielectric

b. conductors separated by an insulator

c. ceramic plates and one mica disc

d. silver-coated insulator

104. The capacitance of a capacitor is NOT influenced by

a. plate thickness

b. plate area

c. plate separation

d. nature of the dielectric

105. A capacitor that stores a charge of 0.5 C at 10 volts has a capacitance of farad.

a. 5

b. 20

c. 10

d. 0.05

106. If dielectric slab of thickness 5 mm and εr = 6 is inserted between the plates of an air capacitor with plate separation of 8 mm, its capacitance is

a. decreased

b. almost doubled

c. almost halved

d. unaffected

107. In a cable capacitor, voltage gradient is maximum at the surface of the

a. sheath

b. conductor

c. insulator

d. earth

108. In Fig. given below voltage across C1 will be ___volt.

a. 100

b. 200

c. 150

d. 300

[pic]

109. The capacitance of a cable capacitor depends on

a. core, diameter

b. insulation thickness

c. ratio of cylinder radii

d. potential difference

110. The insulation resistance of a cable capacitor depends on

a. applied voltage

b. insulation thickness

c. core diameter

d. ratio of inner and outer radii

111. The time constant of an R-C circuit is defined as the time during which capacitor charging current becomes percent of its ___value.

a. 37, final

b. 63, final

c. 63, initial

d. 37, initial

112. The period during which current and voltage changes take place in a circuit is called ______ condition.

a. varying

b. permanent

c. transient

d. steady

113. Which of the following quantity maintains the same polarity during charging and discharging of a capacitor?

a. capacitor voltage

b. capacitor current

c. resistive drop

d. none of the above

114. In a cable capacitor with compound dielectric, voltage gradient is inversely proportional to

a. Permittivity

b. radius of insulating material

c. cable length

d. both (a) and (b)

115. While a capacitor is still connected to a power source, the spacing between its plates is halved. Which of its following quantity would remain constant?

a. field strength

b. plate charge

c. potential difference

d. electric .flux density

116. After being disconnected from the power source, the spacing between the plates of a capacitor is halved. Which of the following quantity would be halved ?

a. plate charge

b. field strength

c. electric flux density

d. potential difference

117 . The main function of a capacitor is to

a. block the current flow

b. help current flow

c. store energy

d. dissipate heat

118. A capacitor that store 0.5 C at 10volt has a capacitance of _____ farad

a. 5

b. 20

c. 10

d. 0.05

119. The output voltage of a lead acid cell is about _______volt

a. 1.5

b. 2.2

c. 1.25

d. 6

Chapter 6 (magnetism)

120. Relative permeability of vacuum is

a. 4π×10-7 H/m

b. 1 H/m

c. 1

d. 1/4π

121. Unit of magnetic flux is

a. weber

b. ampere-turn

c. tesla

d. coulomb

122. Point out the wrong statement

The magnetizing force at the centre of a circular coil varies

a. directly as the number of its turns

b. directly as the current

c. directly as its radius

d. inversely as its radiu

123. A pole of driving admittance function implies

a. zero current for a finite valve of driving voltage

b. zero voltage for a finite valve of driving current

c. an open circuit condition

d. none of (a),(b)and (c)

124. The magnetizing force (H) and magnetic flux density (b) are connected by the relation

a. B =μH

b. B= H/μ0μr

c. B=μ0H/μr

d. B= μ0H/μ0

125. Both the number of turns of its coil and the length of a short solenoid are doubled its Axial magnetizing field would be

a. doubled

b. halved

c. unaffected

d. quadrupled

126. The unit of magnetic – motive force is

a. weber

b. ampere/meter

c. henery

d. ampere-turn /weber

127. Permeability in a magnetic circuit corresponds to in an electric circuit

a. conductivity

b. resistivity

c. conductance

d. resistance

128. point out the WRONG statement

Magnetic leakage is undesirable in electric machine because it

a. leads to their increased weight

b. increase their cost of manufacture

c. produce fringing

d. lower their power efficiency

129. Susceptibility of a magnetic material depends on

a. intensity of magnetization

b. magnetic force

c. mass of the material

d. both (a) and (b)

130. Permanent magnet are normally made of

a. aluminum

b. wrought iron

c. cast iron

d. alnico alloys

131. Those magnetic material are best suited for making armature and transformer cores which have _____ permeability and ____ hystersis loss

a. low , high

b. high, low

c. low, low

d. high, high

132.Those material are well suited for making permanent magnets which have ____ retentivity and ______ correctivity

a. high, high

b. high, low

c. low, low

d. low, high

133. In a magnetic material, hystersis loss takes place primarily due to

a. flux density lag gain behind magnetizing force

b. molar friction

c. its high retentivity

d. rapid reversal of its magnetization

134. Magnets made of low retentivity but high permeability iron are called

a. Electromagnets

b. permanent magnets

c. weak magnets

d. one pole magnets

Chapter 7(eletro-magnetism & induction)

135. The force experience by a current carrying conductor lying parallel to a magnetic field is

a. BI l

b. BI l sinθ

c. Hil

d. zero

136. According to Faraday’s Laws of electromagnetic Induction an e.m.f is induced in a conductor whenever it

a. lies in a magnetic field

b. cuts magnetic flux

c. Moves parallel to the direction of the magnetic field

d. Lies perpendicular to the magnetic flux

137. The magnitude of the induced e.m.f in a conductor depends on the

a. amount of flux cut

b. amount of flux linkages

c. rate of change of flux linkages

d. flux density of the magnetic field

138. The direction of induced e.m.f can be found with the help of

a. Lenz’s law

b. Fleming’s right hand rule

c. Kirchoff’s voltage law

d. Laplace’s law

139. If a current of 5A flowing in a coil of induced 0.1H is reversed in 10ms, e.m.f induced in it is _______ volt

a. 100

b. 50

c. 1

d. 10000

140. Higher the self inductance of a coil,

a. lower the e.m.f induced in it

b. longer the delay in establishing steady current through it

c. greater the flux produced by it

d. lesser its weber turns

141. Mutual inductance between two magnetically coupled coil depends on

a. the number of their turns

b. permeability of the core

c. cross sectional area of their common core

d. all the above

142. Both the number of turns and the core length of an inductive coil are doubled. Its self inductance will be

a. doubled

b. quadrupled

c. halved

d. unaffected

143. Two coil having self inductance of 0.6 H and 0.4 H and a mutual inductance of 0.2 H are connected in series. What is their combined self inductance?

a. 1.4H

b. 0.6H

c. 1.3H

d. either (a) or (b)

144. Two similar coils have a coupling coefficient of 0.25 and a mutual inductance of 0.9 H the self inductance of each coil is ____ henry

a. 0.4

b. 0.6

c. 0.2

d. 0.36

145.Those material are well suited for making permanent magnets which have ____ retentivity and ______ correctivity

a. high, high

b. high, low

c. low, low

d. low, high

146. In a magnetic material, hystersis loss takes place primarily due to

a. flux density lag gain behind magnetizing force

b. molar friction

c. its high retentivity

d. rapid reversal of its magnetization

147. A pole of driving point admittance function implies

a. zero current for a finite value of driving voltage

b. zero voltage for a finite value of driving current

c. an open circuit condition

d. none of the above

Chapter 8 (principle of AC )

148. The power in an AC circuit is given by

a. VI cosθ

b. VI sin θ

c. I2Z

d. I2 XL

149. The p.f of an R-C circuit is

a. often zero

b. between zero and I

c. always unity

d. between zero and 1

150. Which phasor diagram of figure is correct for series R-C circuit

[pic]

151. The input of an a.c circuit having p.f 0.8 lagging is 20 KVA. The power drawn by the circuit is _____KW

a. 12

b. 20

c. 16

d. 8

152. The power factor of an ordinary electric bulb is

a. zero

b. unity

c. slightly more than zero

d. slightly less than unity

153. The rms value of a sinusoidal ac current is equal to its value at an angle of _____ degrees

a. 60

b. 45

c. 30

d. 90

154. The reactance of a coil at 100 Hz is 20Ω.its reactance at 1 kHz would be ____ ohm

a. 2

b. 10

c. 40

d. 200

155. A coil of 2h develops a counter emf of 4v in it .the rate of change of current through it must be _____ amperes/second

a. 2

b. 0.5

c. 8

d. 1

156. If [pic] and [pic], then

a. [pic] lags [pic] by [pic]

b. [pic] lags [pic] by [pic]

c. [pic] leads [pic]by [pic]

d. [pic] is in phase with [pic]

157. From the two voltage equations [pic] and [pic], it is obvious that

a. A leads B by 30o

b. B achieves its maximum value 1/600 second before A does.

c. B lags behind A

d. A achieves its zero value 1/600 second before B.

158. The r.m.s. value of a half wave rectified current is 10 A, its value for full wave rectification would be _____ amperes

a. 20

b. 14.14

c. [pic]

d. [pic]

159. A resultant current is made of two components: a 10 A d.c. component and a sinusoidal component of maximum value 14.14 a. The average value of the resultant current is _____ amperes

a. 0

b.24.14

c. 10

d. 4.14

160. The rms value of a sinusoidal a.c. current is equal to its value at an angle of ___ degree

a. 60

b. 45

c. 30

d. 90

161. For a given line voltage, four heating coils will produce maximum heat when connected

a. all in parallel

b. all in series

c. with two parallel pairs in series

d. one pair in parallel with the other two in series

162. One kWh of energy equals nearly

a. 1000w

b. 860kcal

c. 4186j

d. 735.5w

163. A 100w light bulb burns on an average of 10 hours a day for one week the weekly consumption of energy will be _____ unit/s

a. 7

b. 70

c. 0.7

d. 0.07

Chapter 9 (Single phase A.C circuit)

164. The period during which current and voltage changes take place in a circuit is called ______ condition.

a. varying

b. permanent

c. transient

d. steady

165. In an R-C circuit connected across a d.c. voltage source, which of the following is zero at the beginning of the transient state ?

a. drop across R

b. charging current

c. capacitor voltage

d. none of the above

166. When an R-C circuit is suddenly connected across a d.c. voltage source, the initial rate of charge of capacitor is

a. [pic]

b. [pic]

c. [pic]

d. [pic]

167. During transient rise of current through an R-L circuit, which of the following has maximum intail value

a. circuit current

b. resistive drop

c. oil energy

d. coil voltage

168. In a series R-L circit VL- VR by degree

a. lags 45

b. lags 90

c. leads 90

d. leads,45

169. The voltage applied across an R-L circuit is equal to ____ of VR and VL

a. arithmetic sum

b. algebraic sum

c. phasor sum

d. sum of the square

170. The input of an a.c circuit having p.f 0.8 lagging is 20 KVA. The power drawn by the circuit is _____KW

a. 12

b. 20

c. 16

d. 8

171. The power factor of an a.c. circuit is given by

a. cosine of the phase angle

b. tangent of the phase angle

c. the ratio R/XL

d. the ratio XL /Z

172. In parallel resonant circuit there is practically no difference between the condition for

a. XL =0

b. R=0

c. XC >XL

d. XC ................
................

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