1995 Physics Quiz Bowl (21-40)

21. A diverging lens produces an image of a real object that is:

A. real, inverted, and larger than the object.
B. real, upright, and the same size as the object.
C. virtual, inverted, and smaller than the object.
D. virtual, upright, and larger than the object.
E. virtual, upright, and smaller than the object.

22. A radioactive element has a half-life of 4.0 hours. Approximately how much of the radioactive element will remain after 12.0 hours?

A. 1/16
B. 1/8
C. 1/6
D. 1/4
E. 1/3

23. A Brief History of Time is the title of a book written by:

A. Albert Einstein
B. Stephen Hawking
C. Hendrick Lorentz
D. Isaac Newton
E. Andrew Timex

24. The theoretical (Carnot) efficiency of a heat engine operating between 600º C and 100º C is:

A. 16.7%
B. 20.0%
C. 42.7%
D. 57.3%
E. 83.3%

25. In the figure to the right, equipotential lines are drawn at 0, 20.0 V, and 40.0 V. The total work done in moving a point charge of + 3.00 mC from position a to position b is:

1995ques25diagram.gif (2444 bytes)

A. 4.00 mJ
B. 8.00 mJ
C. 12.0 mJ
D. 24.0 mJ
E. 120 mJ

26. Two positive point charges repel each other with force 0.36 N when their separation is 1.5 m. What force do they exert on each other when their separation is 1.0 m?

A. 0.81 N
B. 0.54 N
C. 0.36 N
D. 0.24 N
E. 0.16 N

27. A rocket near the surface of the earth is accelerating vertically upward at 10 m/s². The rocket releases an instrument package. Immediately after release the acceleration of the instrument package is:

A. 20 m/s² up
B. 10 m/s² up
C. 0
D. 10 m/s² down
E. 20 m/s² down

29. Two objects, P and Q, have the same momentum. Q can have more kinetic energy than P if it:

A. has more mass than P.
B. has the same mass as P.
C. is moving faster than P.
D. is moving at the same speed as P.
E. None of the above. Q can’t have more kinetic energy than P.

30. A 0.20 m long copper rod has constant velocity 0.30 m/s traveling through a uniform magnetic field of 0.060 T. The rod, velocity, and magnetic field are all mutually perpendicular. What is the potential difference induced across the rod’s length?

A. 0.0036 V
B. 0.040 V
C. 0.090 V
D. 1.0 V
E. 25 V

31. A beam of light passes from medium 1 to medium 2 to medium 3 as shown in the accompanying figure. What is true about the respective indices of refraction (n₁, n₂, and n₃)?

1995ques31diagram.gif (1387 bytes)

A. n₁ > n₂ > n₃
B. n₁ > n₃ > n₂
C. n₂ > n₃ > n₁
D. n₂ > n₁ > n₃
E. n₃ > n₁ > n₂

32. Four identical light bulbs K, L, M, and N are connected in the electrical circuit shown in the accompanying figure. Bulb K burns out. Which of the following statements is true?

1995ques32diagram.gif (1767 bytes)

A. All the light bulbs go out.
B. Only bulb N goes out.
C. Bulb N becomes brighter.
D. The brightness of bulb N remains the same.
E. Bulb N becomes dimmer but does not go out.

33. An atomic particle of mass m moving at speed v is found to have wavelength l. What is the wavelength of a second particle with speed 3v and the same mass?

A. (1/9) l
B. (1/3) l
C. l
D. 3 l
E. 9 l

34. A student pulls a wooden box along a rough horizontal floor at constant speed by means of a force P as shown to the right. Which of the following must be true?

1995ques34diagram.gif (1668 bytes)

A. P > f and N < W.
B. P > f and N = W.
C. P = f and N > W.
D. P = f and N = W.
E. P < f and N = W.

35. The voltmeter in the accompanying circuit diagram has internal resistance 10.0 kW and the ammeter has internal resistance 25.0 W. The ammeter reading is 1.00 mA. The voltmeter reading is most nearly:

1995ques35diagram.gif (1998 bytes)

A. 1.0 V
B. 2.0 V
C. 3.0 V
D. 4.0 V
E. 5.0 V

36. Assume the electric potential is zero at infinity. A point charge of +4.0 mC is placed on the negative x-axis 0.20 m to the left of the origin, as shown in the accompanying figure. A second point charge q is placed on the positive x-axis 0.30 m to the right of the origin. The net electric potential at the origin is also zero. What is q’s charge?

1995ques36diagram.gif (1657 bytes)

A. –9.0 mC
B. –6.0 mC
C. 0
D. +6.0 mC
E. +9.0 mC

37. A spring is compressed between two objects with unequal masses, m and M, held together by a string as shown in the figure to the right. The objects are initially at rest on a horizontal frictionless surface. The string is then cut. Which statement is true?

1995ques37diagram.gif (1432 bytes)

A. Kinetic energy is the same as before the string was cut.
B. The total final kinetic energy is zero.
C. The two objects have equal kinetic energy.
D. The speed of one object is equal to the speed of the other.
E. The total final momentum of the two objects is zero.

38. A block with initial velocity 4.0 m/s slides 8.0 m across a rough horizontal floor before coming to rest. The coefficient of friction is:

A. 0.80
B. 0.40
C. 0.20
D. 0.10
E. 0.05

39. A car starts from rest and accelerates at 0.80 m/s² for 10 s. It then continues at constant velocity. Twenty seconds (20 s) after it began to move, the car has:

A. velocity 8.0 m/s and has traveled 40 m.
B. velocity 8.0 m/s and has traveled 80 m.
C. velocity 8.0 m/s and has traveled 120 m.
D. velocity 16 m/s and has traveled 160 m.
E. velocity 16 m/s and has traveled 320 m.

40. A Metrologic^Ò laser is embedded in a material of index of refraction n. The laser beam emerges from the material and hits a target. See the accompanying figure for the position parameters of the laser and target. The value of n is:

1995ques40diagram.gif (2799 bytes)

A. 1.4
B. 1.5
C. 2.1
D. 3.5
E. 5.0