AP Physics - Oak Park Independent



AP Physics Name _________________________

Practice Units 1-5 Multiple Choice (60 %) Period _____

Questions 1-3

[pic]

A projectile is fired with initial velocity vo = 20 m/s at an angle θo = 30o with the horizontal and follows the trajectory shown above.

1. The speed of the ball when it reaches its highest point is closest to

(A) 20 m/s (B) 17 m/s (C) 10 m/s (D) 0 m/s

2. Which of the following diagrams best shows the direction of the acceleration of the ball at its highest point?

(A) ⋄ (B) ™ (C) ® (D) ⎛

3. The speed of the ball just before it strikes the ground is closest to

(A) 20 m/s (B) 17 m/s (C) 10 m/s (D) 0 m/s

4. A body moving in the positive x direction passes the origin at time t = 0. Between t = 0 and t = 1 second, the body has a constant speed of 8 m/s. At t = 1 second, the body is given a constant acceleration of -2 m/s2. The position x of the body at t = 11 seconds is

(A) + 36 m (B) + 24 m (C) - 12 m (D) - 24 m

5. An object is released from rest on a planet that has no atmosphere. The object falls freely for 6.0 m in 1.0 s. What is the magnitude of the acceleration due to gravity on the planet?

(A) 0.5 m/s2 (B) 3.0 m/s2

(C) 6.0 m/s2 (D) 12 m/s2

6. The velocity v of an object moving along the x-axis is shown above as a function of time t.

|v | |

| | |

| | t |

The acceleration of this object is most likely

(A) zero (B) constant but not zero

(C) increasing (D) decreasing

7. A truck travels at 10 m/s for 1000 m, and then it travels at 20 m/s for 500 m. The magnitude of the average velocity of the truck is most nearly

(A) 12 m/s (B) 14 m/s (C) 15 m/s (D) 16 m/s

Questions 8-9

velocity (m/s)

|1 | | | | | | |

| | | | | | | |

| | | | |

| |time (s) |

8. The graph above shows the velocity versus time for an object moving in a straight line. At what time after time = 0 does the object again pass through its initial position?

(A) 1 s (B) 2 s (C) 3 s (D) 5 s

9. For what time interval is the object moving with constant negative acceleration?

(A) between 0 s and 1 s (B) between 1 s and 2 s

(C) between 2 s and 5 s (D) between 5 s and 6 s

10. A ball is thrown horizontally at 10 m/s off the edge of a vertical cliff and lands in the water a distance of 50 m from the base of the cliff. How far from the base of the cliff would the ball have landed if it initially had been moving horizontally with speed 15 m/s?

(A) 50 m (B) 75 m (C) 100 m (D) 200 m

11. A car accelerates uniformly from rest, reaching a speed of 20 m/s in 4 s. During the 4 s, the car has traveled

(A) 15 m (B) 30 m (C) 40 m (D) 90 m

12. An object is dropped from rest from the top of a 400 m cliff on earth. If air resistance is negligible, what is the distance the object travels during the first 4 s of its fall?

(A) 30 m (B) 80 m (C) 120 m (D) 160 m

13. A rock is dropped from the top of a 45-m tower, and at the same time a ball is thrown from the top of the tower in a horizontal direction. Air resistance is negligible. The ball and the rock hit the level ground a distance of 15 m apart. The horizontal velocity of the ball thrown was most nearly

(A) 5 m/s (B) 10 m/s (C) 14.1 m/s (D) 20 m/s

14. Two people are in a boat that is capable of a maximum speed of 5 km/hr in still water, and wish to cross a river

3 km wide to a point directly across from their starting point. If the speed of the water in the river is 4 km/hr, how much time is required for the crossing?

(A) 3/5 hr (B) 3/4 hr (C) 1 hr (D) 5/3 hr

15. A projectile is fired from the surface of the earth with a speed of 100 m/s at an angle of 30° above the horizontal. If the ground is level, what is the maximum height reached by the projectile?

(A) 100 m (B) 125 m (C) 250 m (D) 500 m

16. A spring-loaded gun can fire a projectile to a height h if it is fired straight up. If the same gun is pointed at an angle of 30° from horizontal, what maximum height can now be reached by the projectile?

(A) h/4 (B) h/2√2 (C) h/2 (D) h/√2

17. A ball falls straight down through the air under the influence of gravity. The acceleration due to air resistance is given by the equation, a = 0.22v2. What is the maximum velocity of the ball?

(A) 3.3 m/s (B) 5.0 m/s

(C) 6.7 m/s (D) 10 m/s

Questions 18-19 A block of mass 3 kg, initially at rest, is pulled along a frictionless, horizontal surface with a force shown as a function of time t by the graph.

[pic]

18. The acceleration of the block at t = 3 s is

(A) 1 m/s2 (B) 2 m/s2 (C) 4 m/s2 (D) 8 m/s2

19. The speed of the block at t = 3 s is

(A) 1 m/s (B) 3 m/s (C) 4 m/s (D) 6 m/s

20. A horizontal force F pushes a 1-kg block against a vertical wall. The coefficient of friction between the block and the wall is 0.25.

[pic]

What value of F is necessary to keep the block from slipping down the wall?

(A) 10 N (B) 20 N (C) 30 N (D) 40 N

21. A 10-kg block is pulled along a horizontal surface by a 50-N force, which acts at an angle of 30o with the horizontal.

[pic]

The normal force exerted on the block by the surface is

(A) 25 N (B) 50 N (C) 75 N (D) 100 N

22. A block of mass 5 kg lies on an inclined plane. The coefficient of friction between the plane and the block is 0.2.

[pic]

The magnitude of the force F necessary to pull the block up the plane with constant speed is most nearly

(A) 32 N (B) 38 N (C) 45 N (D) 53 N

23. A rope of negligible mass supports a 20-N block. The breaking strength of the rope is 50 N. The largest acceleration that can be given to the block by pulling up on it with the rope without breaking the rope is most nearly

(A) 6 m/s2 (B) 6.7 m/s2

(C) 10 m/s2 (D) 15 m/s2

Questions 24-25 A cylinder (m = 2 kg, r = 0.5 m, β = ½) rotates with constant perimeter velocity of 2 m/s about a fixed axis.

24. What is the angular momentum of the cylinder?

(A) 1 kg•m2/s (B) 2 kg•m2/s

(C) 3 kg•m2/s (D) 4 kg•m2/s

25. What is the kinetic energy of the cylinder?

(A) 1 J (B) 2 J

(C) 3 J (D) 4 J

[pic]

26. An object of mass m is moving with speed vo to the right on a horizontal frictionless surface, as shown above, when it explodes into two pieces. Subsequently, one piece of mass ⅓m moves with a speed ½vo to the left. The speed of the other piece of the object is

(A) vo/2 (B) vo/3 (C) 7vo/4 (D) 3vo/2

Questions 27-28 A system consists of two objects having masses m1 = 1 kg and m2 = 3 kg. The objects are connected by a massless string, hung over a pulley as shown above, and then released.

27. What is the acceleration of the system?

(A) 2 m/s2 (B) 4 m/s2 (C) 5 m/s2 (D) 10 m/s2

28. When the speed of each object is 1 m/s, the magnitude of the total linear momentum of the system is

(A) 1 kg•m/s (B) 2 kg•m/s (C) 3 kg•m/s (D) 4 kg•m/s

29. When the object of mass m2 has descended 1 m, the potential energy of the system has decreased by

(A) 10 J (B) 20 J (C) 30 J (D) 40 J

30. A satellite of mass M moves in a circular orbit of radius R with constant speed v. True statements about this satellite include which of the following?

I. Its angular speed is vIR.

II. Its tangential acceleration is zero.

III. Its centripetal acceleration is v2/R.

(A) I only (B) II only (C) I and III only (D) I, II, and III

31. Two objects of mass 0.2 kg and 0.1 kg, respectively, move parallel to the x-axis. The 0.2 kg object overtakes and collides with the 0.1 kg object. Immediately after the collision, the y-component of the velocity of the 0.2 kg object is 2 m/s upward.

[pic]

What is the y-component of the velocity of the 0.1 kg object immediately after the collision?

(A) 4 m/s downward (B) 2 m/s downward

(C) 0 m/s (D) 2 m/s upward

32. A 1-kg block is moving horizontally to the right at 2 m/s on a table with negligible friction when it collides with a 2-kg block moving horizontally to the right at 1 m/s at the moment of impact. The two blocks stick together upon impact.

2 m/s 1 m/s

The speed of the composite body immediately after the collision is

(A) 1 m/s (B) 2/3 m/s (C) ¾ m/s (D) 4/3 m/s

33. A car is moving clockwise around a circular track of radius 100 m at a speed of 10 m/s. At the instant when the car is traveling east, the acceleration is

(A) directed north at 1 m/s2

(B) directed south at 1 m/s2

(C) directed east at 1 m/s2

(D) directed south at 2 m/s2

34. A person weighing 400 N on earth travels to another planet with twice the mass and twice the radius of earth. The person's weight on this other planet is most nearly

(A) 100 N (B) 200 N (C) 400 N (D) 800 N

35. A light rigid rod with masses attached to its ends is pivoted about a horizontal axis.

[pic]

What is the net torque, τ, on the object?

(A) MogL (B) 2MogL (C) 3MogL (D) 4MogL

36. The horizontal turntable rotates at a constant rate. As viewed from above, a coin on the turntable moves counterclockwise in a circle.

[pic]

Which of the following vectors represents the direction of the centripetal acceleration and velocity on the coin when the coin is in the position shown?

(A) ac: ⇓ v: ⇓ (B) ac: ∑ v: ∑

(C) ac: 〈 v: ⇓ (D) ac: ® v: ⇓

37. The radius of the earth is approximately 6,000 km. The acceleration of an astronaut in a perfectly circular orbit 6000 km above the earth's surface would be most nearly

(A) 0 m/s2 (B) 2.5 m/s2

(C) 5 m/s2 (D) 7.5 m/s2

38. A 1-kg ball is dropped from the top of a 50-m-high building. If the ball reaches the ground with a speed of 30 m/s, the energy lost to friction is most nearly

(A) 0 J (B) 50 J (C) 250 J (D) 450 J

Questions 39-40 A horizontal, uniform board of weight 100 N and length 4 m is supported by vertical chains at each end. A person weighing 400 N is sitting on the board. The tension in the right chain is 250 N.

39. What is the tension in the left chain?

(A) 250 N (B) 375 N (C) 500 N (D) 625 N

40. How far from the left end of the board is the person sitting?

(A) 0.4 m (B) 1.5 m (C) 2 m (D) 2.5 m

41. A 5-m uniform plank of mass 150 kg rests on the top of a building with 2 m extended over the edge as shown above.

[pic]

How far can a 50-kg person venture past the edge of the building on the plank before the plank just begins to tip?

(A) 0.5 m (B) 1 m (C) 1.5 m (D) 2 m

42. A wheel, R = 1.0 m, and negligible mass is mounted on a horizontal frictionless axle so that the wheel is in a vertical plane. Masses, M = 2 kg and 2M = 4 kg, are mounted on the rim of the wheel.

[pic]

A third mass, m, is placed on the wheel so that it is in static equilibrium, what is m?

(A) 1 kg (B) 2 kg (C) 3 kg (D) 4 kg

43. A system of two wheels fixed to each other is free to rotate about a frictionless axis through the common center of the wheels and perpendicular to the page. Four forces are exerted tangentially to the rims of the wheels.

[pic]

The magnitude of the net torque on the system is

(A) FR (B) 2FR (C) 3FR (D) 5FR

44. An object weighing 300 N is suspended by means of two cords.

[pic]

The tension in the 45o cord is

(A) 0 N (B) 176 N (C) 215 N (D) 424 N

45. If an object is in rotational and translational equilibrium, which of the following must be true?

I. ∑τ = 0 II. ∑F|| = 0 III. ∑F⊥ = 0

(A) I only (B) II only (C) I, III only (D) I, II, and III

46. If one knows only the constant force acting on an object and the parallel distance during which this force acts, one can determine the

(A) change in momentum of the object

(B) change in potential energy of the object

(C) change in kinetic energy of the object

(D) work done on the object

47. Two pucks are attached by a stretched spring and are initially held at rest on a frictionless surface. The pucks are then released simultaneously.

[pic]

If puck I has three times the mass of puck II, which of the following is the same in magnitude for both pucks as the spring pulls the two pucks toward each other?

(A) v (B) a (C) K (D) p

Questions 48-49

A 2-kg sphere (β = 2/5) is released from rest at height, h = 0.80 m, at the top of a ramp.

48. If the ramp is frictionless, what is the speed v of the sphere at the bottom of the incline?

(A) 2.8 m/s (B) 3.0 m/s (C) 3.4 m/s (D) 4.0 m/s

49. If the ramp has friction so that the sphere rolls without slipping, what is the speed v at the bottom of the ramp?

(A) 2.8 m/s (B) 3.0 m/s (C) 3.4 m/s (D) 4.0 m/s

50. What is the kinetic energy of the sphere at the bottom of the ramp?

(A) 4 J (B) 8 J (C) 12 J (D) 16 J

51. A ball is dropped from the top of a high cliff. Which of the graphs best represents the ball's kinetic energy K as a function of time t?

(A) (B)

(C) (D)

52. A student weighing 500 N climbs at constant speed to the top of an 10 m vertical rope in 10 s. The average power expended by the student to overcome gravity is most nearly

(A) 100 W (B) 200 W (C) 500 W (D) 1000 W

Questions 53-54 A sphere, m1 = 1 kg, which is attached to a spring, is displaced downward from its equilibrium position and released from rest. A sphere, m2 = 2 kg, which is suspended from a string of length l = 1 m, is displaced to the right and released from rest so that it swings as a simple pendulum with small amplitude. Assume that both spheres undergo simple harmonic motion.

[pic]

53. Which of the following is true for both spheres?

(A) The minimum kinetic energy is attained as the spheres pass through their equilibrium positions.

(B) The maximum kinetic energy is attained as the spheres reach their points of release.

(C) The maximum potential energy is attained as the spheres pass through their equilibrium positions.

(D) The energies at the equilibrium position and the point of release are equal.

54. If both spheres have the same period of oscillation, what is k for the spring?

(A) 10 N/m (B) 20 N/m (C) 40 N/m (D) 50 N/m

55. A 10-kg object is suspended from the center of a massless string, where θ = 20o.

[pic]

The tension in the string is

(A) 27 N (B) 53 N (C) 66 N (D) 75 N

Questions 56-66 A 0.1-kg block is attached to an initially unstretched spring (k = 10 N/m). The block is released from rest at t = 0.

56. What is the amplitude of the resulting simple harmonic motion?

(A) 0.05 m (B) 0.10 m (C) 0.15 m (D) 0.20 m

57. What is the total distance that the block travels before it returns to its initial position?

(A) 0.1 m (B) 0.2 m (C) 0.3 m (D) 0.4 m

58. At what time after release will the block first return to its initial position?

(A) 0.2 s (B) 0.3 s (C) 0.4 s (D) 0.6 s

59. What is the maximum speed of the block?

(A) 0.5 m/s (B) 1.0 m/s (C) 1.5 m/s (D) 2.0 m/s

60. What is the total energy of the oscillating block?

(A) 0.01 J (B) 0.02 J (C) 0.03 J (D) 0.05 J

61. What is the maximum acceleration of the block?

(A) 5.0 m/s2 (B) 7.5 m/s2 (C) 10 m/s2 (D) 15 m/s2

62. The 0.1-kg block is replaced by block B, which oscillates with a period of 2 s. What is the mass of block B?

(A) 1 kg (B) 2 kg (C) 3 kg (D) 5 kg

63. The spring is replaced with a stiffer spring (k = 20 N/m). What would be the effect on the amplitude and period of oscillation of block B?

(A) amplitude and period increase

(B) amplitude and period decrease

(C) amplitude increases and period decreases

(D) amplitude decreases and period increases

64. A pendulum is made using block B as a bob on the end of a string. What is the length of the string if the pendulum has a period of 2 s?

(A) 0.25 m (B) 0.50 m (C) 0.75 m (D) 1.0 m

65. Block B on the end of the string from question 14 is replaced by the 0.1-kg block. What is the period of oscillation for the new pendulum?

(A) 1 s (B) 2 s (C) 3 s (D) 4 s

66. The original spring (k = 10 N/m) and block B are transported to Mars, where gmars = 4 m/s2. What is the period of SHM?

(A) 1 s (B) 2 s (C) 3 s (D) 4 s

67. A 5-kg block slides on a horizontal frictionless table with an initial speed 10 m/s. It then compresses a spring with a spring constant, k = 500 N/m and is brought to rest. How much is the spring compressed from its natural length?

(A) 0.10 m (B) 0.25 m (C) 0.50 m (D) 1.0 m

Questions 68-69 refer to the graph below of the displacement x (m) versus time t (s) for a particle in simple harmonic motion.

[pic]

68. Which of the following graphs shows the kinetic energy K of the particle as a function of time t for one cycle of motion?

(A) (B)

(C) (D)

69. Which of the following graphs shows the kinetic energy K of the particle as a function of its displacement x?

(A) (B)

(C) (D)

70. The following graphs, all drawn to the same scale, represent the net force F as a function of displacement x for an object that moves along a straight line. Which graph represents the force that will cause the LEAST change in the kinetic energy of the object from x = 0 to x = x1?

(A) (B)

(C) (D)

AP Physics Name _________________________

Practice Units 1-5 Free Response (60 %) Period _____

1. A 0.50 kg cart moves on a straight horizontal track. The graph of velocity vx versus time t for the cart is given below.

[pic]

a. Indicate every time t for which the cart is at rest.

b. Indicate every time interval for which the speed (magnitude of velocity) of the cart is increasing.

c. Determine the horizontal position x of the cart at t = 9.0 s if the cart is located at x = 2.0 m at t = 0.

d. Sketch the acceleration a versus time t graph for the motion of the cart from t = 0 to t = 25 s.

e. From t = 25 s until the cart reaches the end of the track, the cart continues with constant horizontal velocity. The cart leaves the end of the track and hits the floor, which is 0.40 m below the track. Neglecting air resistance, determine each of the following.

(1) The time from when the cart leaves the track until it first hits the floor

(2) The horizontal distance from the end of the track to the point at which the cart first hits the floor

(3) The kinetic energy of the cart immediately before it hits the floor

2. Several students are riding in bumper cars at an amusement park. The combined mass of car A and its occupants is 250 kg. The combined mass of car B and its occupants is 200 kg. Car A is 15 m away from car B and moving to the right at 2.0 m/s when the driver decides to bump into car B, which is at rest.

a. Car A accelerates at 1.5 m/s2 to a speed of 5.0 m/s and then continues at constant velocity until it strikes car B. Calculate the total time for car A to travel the 15 m.

b. After the collision, car B moves to the right at a speed of 4.8 m/s.

(1) Calculate the speed of car A after the collision.

(2) Is the direction of motion of car A after the collision to the left, right or is it at rest? Justify your answer.

c. Is this an elastic collision? Justify your answer.

3.

A spring of unstretched length 0.20 m is placed horizontally on a frictionless table. One end of the spring is fixed and the other end is attached to a block of mass M = 8.0 kg. The 8.0 kg block is also attached to a massless string that passes over a small frictionless pulley. A block of mass m = 4.0 kg hangs from the other end of the string. When this spring-and-blocks system is in equilibrium, the length of the spring is 0.25 m and the 4.0 kg block is 0.70 m above the floor.

a. Draw free-body diagrams showing and labeling the forces on each block when the system is in equilibrium.

b. Calculate the tension in the string.

c. Calculate the force constant of the spring.

The string is now cut at point P.

d. Calculate the time taken by the 4.0 kg block to hit the floor.

e. Calculate the frequency of oscillation of the 8.0 kg block.

f. Calculate the maximum speed attained by the 8.0 kg block.

4. A simple pendulum consists of a bob of mass 1.8 kg attached to a string of length 2.3 m. The pendulum is held at an angle of 30° from the vertical by a light horizontal string attached to a wall.

[pic]

a. Draw a free-body diagram showing and labeling the forces on the bob in the position shown above.

b. Calculate the tension in the horizontal string.

c. The horizontal string is now cut close to the bob, and the pendulum swings down. Calculate the speed of the bob at its lowest position.

5. Blocks 1 and 2 of masses m1 and m2 respectively, are connected by a light string, as shown above. These blocks are further connected to a block of mass M by another light string that passes over a pulley of negligible mass and friction. Blocks 1 and 2 move with a constant velocity v down the inclined plane, which makes an angle θ with the horizontal. The kinetic frictional force on block 1 is f and that on block 2 is 2f.

[pic]

a. Draw and label all the forces on block m1.

Express your answers to each of the following in terms of m1, m2, g, θ, and f.

b. Determine the coefficient of kinetic friction between the inclined plane and block 1.

c. Determine the value of the suspended mass M that allows blocks 1 and 2 to move with constant velocity down the plane.

d. The string between blocks 1 and 2 is now cut. Determine the acceleration of block 1 while it is on the inclined plane.

AP Physics Name _________________________

Practice Units 6-7 (40 %) Period _____

Multiple Choice

1. Helium (42He) mass mHe is related to the neutron mass mn and the proton mass mp by which of the following?

(A) mHe = 2(mn – mp)

(B) mHe = 4mn + 2mp

(C) mHe = 2(mn + mp)

(D) mHe = 2(mn + mp) – (mass equivalent to binding energy)

2. When 14N is bombarded by alpha particles, a proton is emitted. If the 14N target is stationary, the kinetic energy of the reaction products is equal to the

(A) kinetic energy of the alpha particle

(B) total energy of the alpha particle

(C) energy equivalent of the mass decrease in the reaction

(D) energy equivalent of the mass decrease in the reaction, plus the kinetic energy of the alpha particle

3. A negative beta particle and a gamma ray are emitted during the radioactive decay of a nucleus of 146C. Which of the following is the resulting nucleus?

(A) 104Be (B) 135B (C) 156C (D) 147N

4. 147N + 42He → 178O + _____

The additional product of the nuclear fission reaction shown above is

(A) 11H (B) 21H (C) 01e (D) 0-1e

5. At 12:30 P.M. a radioactive sample decays at a rate of 4,000 counts per minute. At 1:00 P.M. the decay rate has decreased to 2,000 counts/minute. The decay rate at noon was

(A) 0 counts/minute (B) 500 counts/minute

(C) 1,000 counts/minute (D) 8,000 counts/minute

6. Two wave pulses, each of wavelength λ, are traveling toward each other along a rope as shown above.

[pic]

When both pulses are in the region between points X and Y, which are a distance λ apart, the shape of the rope will be which of the following?

(A) (B)

(C) (D)

Questions 7-9 A string has a mass of 0.2 kg and is stretched with a force of 40 N. The second harmonic shown below has a frequency of 10 Hz.

[pic]

7. The speed of the wave on the string is

(A) 5 m/s (B) 10 m/s (C) 15 m/s (D) 20 m/s

8. The frequency of the first harmonic is

(A) 5 Hz (B) 10 Hz (C) 15 Hz (D) 20 Hz

9. The wavelength of the third harmonic is

(A) 0.75 m (B) 1 m (C) 1.33 m (D) 1.5 m

10. The tension in the string is increased to 90 N. What is the resulting wave velocity?

(A) 10 m/s (B) 20 m/s (C) 30 m/s (D) 40 m/s

11. In the Doppler effect for sound waves, factors that affect the frequency that the observer hears include which of the following?

I. The speed of the source

II. The speed of the observer

III. The frequency of the sound

(A) I only (B) III only (C) I and II only (D) I, II, and III

12. A train whistle has a frequency of 100 Hz as heard by the engineer on the train. Assume that the velocity of sound in air is 330 m/s. If the train is pulling away from a stationary listener on a windless day at a velocity of 30 m/s, the whistle frequency that the listener hears is most nearly

(A) 85 Hz (B) 90 Hz (C) 100 Hz (D) 110 Hz

13. What happens to the velocity, frequency and wavelength of light when it passes from glass to air?

Velocity Frequency Wavelength

(A) Increases Remains the same Increases

(B) Decreases Remains the same Decreases

(C) Increases Increases Remains the same

(D) Remains the same Decreases Decreases

[pic]

14. Light leaves a source at X and travels to Y along the path shown above. Which of the following statements is correct?

(A) The index of refraction is the same for the two media.

(B) Light travels faster in medium 1 than medium 2.

(C) The wavelength of light is shorter in medium 1 than medium 2.

(D) The angle of refraction is greater in medium 2.

Questions 15-19 Consider the four optical arrangements where the arrow represents the object and f is the location of focus.

(A) (B) (C) (D)

• • •

f f f

plane convex convex convex

mirror mirror lens lens

15. Which arrangement would generate an inverted image?

16. Which arrangement would be used to form a magnified upright image?

17. Which arrangement would generate an upright image that is the same size as the object?

18. Which arrangement would generate an upright image that is smaller than the object?

19. The index of refraction for a transparent material is 1.41. What is the critical angle in air?

(A) 30o (B) 45o (C) 60o (D) 90o

Questions 20-23 Consider the four locations along the major axis of a spherical mirror with center of curvature at c and focal point at b.

[pic]

20. Where would you place an object in order to produce an upright magnified image?

21. Where would you place an object in order to produce an inverted image of equal size to the object?

22. Where would you place an object in order to produce an inverted image that is smaller than the object?

23. Where would you place a light source in order to generate parallel rays of light?

24. An object is placed 3 m from a lens whose focal length is 1.5 m. The image is

(A) inverted, real, and on the opposite side from the object.

(B) inverted, virtual, and on the same side from the object.

(C) upright, real, and on the same side as the object.

(D) upright, virtual, and on the same side as the object.

25. A large lens is used to focus an image of an object onto a screen. If the top half of the lens is covered with a dark card, which of the following occurs?

(A) The top half of the image disappears.

(B) The bottom half of the image disappears.

(C) The image becomes smaller.

(D) The image becomes dimmer.

26. An object is placed on the axis of a diverging thin lens

(f = -2 cm), at a distance of 8 cm from the lens. The distance between the image and the lens is most nearly

(A) 0.4 cm (B) 0.8 cm (C) 1.6 cm (D) 2.7 cm

27. 600-nm light passes through two slits. The first-order interference maximum appears at 6°. The separation of the slits is most nearly

(A) 600 nm (B) 450 nm (C) 300 nm (D) 150 nm

28. A soap bubble in air has an index of refraction, n = 2. A beam of light is incident normally on the bubble. If the light has wavelength, λfilm, in soap, maximum destructive interference between the incident beam and the reflected beam occurs when the thickness of the bubble is

(A) 2λfilm (B) λfilm (C) ½λfilm (D) ¼λfilm

29. If photons of light of wavelength, λ, have momentum p, photons of light of wavelength, 2λ, will have a momentum of

(A) 2 p (B) 4 p (C) ½ p (D) ¼ p

Questions 30-31 A hypothetical atom has three energy states as shown below.

|Energy |-2 | |n = 3 |

|(eV) | | | |

| | | | |

| |-4 | |n = 2 |

| | | | |

| | | | |

| |-7 | |n = 1 |

| | | | |

| | | | |

30. Which of the following photon energies could NOT be found in the emission spectra of this atom after it has been excited to the n = 3 state?

(A) 1 eV (B) 2 eV (C) 3 eV (D) 5 eV

31. Which transition will produce the photon with the shortest wavelength?

(A) n = 2 to n = 1 (B) n = 3 to n = 1

(C) n = 1 to n = 2 (D) n = 3 to n = 2

Questions 32-34 For each question choose an answer from the following graphs.

(A) (B)

(C) (D)

32. Which graph shows the maximum kinetic energy of photoelectrons versus the frequency of the incident light?

33. Which graph shows the energy of a photon versus the frequency?

34. Which graph shows the de Broglie wavelength versus the linear momentum?

35. How should a student adjust a photocell in order to produce more photoelectrons per unit time with more kinetic energy per electron?

(A) Increase the intensity and decrease the wavelength of the light.

(B) Increase the intensity and the wavelength of the light.

(C) Decrease the intensity and the wavelength of the light.

(D) Decrease the intensity and increase the wavelength of the light.

36. Electrons that have 150 eV of energy have a de Broglie wavelength of 10 nm. How much energy do electrons with de Broglie wavelength of 20 nm?

(A) 37.5 eV (B) 75 eV (C) 300 eV (D) 600 eV

Free Response

37. You are asked to experimentally determine the focal length of a converging lens.

a. Sketch the setup used to obtain the object distance, do, and the image distance, di. Label the lens, screen, candle, do and di.

b. Complete the last two columns for the following data.

|Trial # |do (m) |di (m) |1/do (m-1) |1/di (m-1) |

|1 |0.40 |1.10 | | |

|2 |0.50 |0.75 | | |

|3 |0.60 |0.60 | | |

|4 |0.80 |0.50 | | |

|5 |1.20 |0.38 | | |

c. Graph 1/di (y-axis) and 1/do (x-axis) and draw a best-fit line through the points.

|3.5 | | | | | | | |

| | | | | | | | |

(1) How can you use the graph to determine the focal length of the lens?

(2) Determine the focal length.

d. Sketch a 2-ray diagram showing the position of the image from trial 1 above.

38. A positron (positively charged electron) and electron are forced to collide at low velocity. As a result they annihilate each other, creating two photons of equal energy moving in opposite directions. Determine the following.

a. Energy generated (in J)

b. Energy of each photon (in eV)

c. Wavelength of each photon (in nm)

d. Momentum of each photon (in kg•m/s)

e. Total momentum of both photons (in kg•m/s)

-----------------------

1 kg

2 kg

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