AAPT Quiz
2007 Physics Quiz Bowl (Part 2)
26. For the diagram shown below, what is the ratio of the charges q
_{2}
/q
_{1}
, where the diagram shown has a representation of the field lines in the space near the charges.
-3/2
-2/3
2/3
3/2
1
27. A junior Thomas Edison wants to make a brighter light bulb. He decides to modify the filament. How should the filament of a light bulb be modified in order to make the light bulb produce more light at a given voltage?
A. Increase the resistivity only.
B. Increase the diameter only.
C. Decrease the diameter only.
D. Decrease the diameter and increase the resistivity.
E. Increase the length only.
28. Which statement about a system of point charges that are fixed in space is necessarily true?
A. If the potential energy of the system is negative, net positive work by an external agent is required to take the charges in the system back to infinity.
B. If the potential energy of the system is positive, net positive work is required to bring any new charge not part of the system in from infinity to its final resting location.
C. If the potential energy of the system is zero, no negative charges are in the configuration.
D. If the potential energy of the system is negative, net positive work by an external agent was required to assemble the system of charges.
E. If the potential energy of the system is zero, then there is no electric force anywhere in space on any other charged particle not part of the system.
29. In the circuit diagram below, all of the bulbs are identical. Which bulb will be the brightest?
A
B
C
D
E. The bulbs all have the same brightness.
30. In the following circuit diagram, which one of the bulbs will not light?
A
B
C
D
They all light.
31. James Clerk Maxwell's great contribution to electromagnetic theory was his idea that
A. work is required to move a magnetic pole through a closed path surrounding a current.
B. a time-changing electric field acts as a current and produces a magnetic field.
C. the speed of light could be determined from simple electrostatic and magnetostatic experiments and finding the values of µ
_{o}
and episolon
_{o}
.
D. the magnetic force on a moving charge particle is perpendicular to both its velocity and the magnetic field
E. magnetism can be explained in terms of circulating currents in atoms
32. What does LASER stand for?
A. Light Amplification by Simulated Emission of Radiation
B. Light Amplification by Stimulated Emission of Radiation
C. Light Amplification by Simultaneous Emission of Radiation
D. Light Amplification by Systematic Emission of Radiation
E. Light Amplification by Serendipitous Emission of Radiation
33. For the circuit shown, the ammeter reading is initially I. The switch in the circuit then is closed.
Consequently:
A. The ammeter reading decreases.
B. The potential difference between E and F increases
C. potential difference between E and F stays the same
D. Bulb #3 lights up more brightly.
E. The power supplied by the battery decreases.
34. For the solenoids shown in the diagram (which are assumed to be close to each other), the resistance of the left-hand circuit is slowly increased.
In which direction does the galvanometer needle in the right-hand circuit move in response to this change?
A. The needle deflects to the left.
B. The needle deflects to the right.
C. The needle oscillates back and forth.
D. The needle rotates in counterclockwise.
E. The needle never moves.
35. Two objects labeled K and L have equal mass but densities 0.95D
_{o}
and D
_{o}
, respectively. Each of these objects floats after being thrown into a deep swimming pool. Which is true about the buoyant forces acting on these objects?
A. The buoyant force is greater on Object K since it has a lower density and displaces more water.
B. The buoyant force is greater on Object K since it has lower density and lower density objects always float “higher” in the fluid.
C. The buoyant force is greater on Object L since it is denser than K and therefore “heavier.”
D. The buoyant forces are equal on the objects since they have equal mass.
E. Without knowing the specific gravity of the objects, nothing can be determined.
36. A driveway is 22.0 m long and 5.0 m wide. If the atmospheric pressure is 1.0 x 10
^{5}
Pa, what force does the atmosphere exert on the driveway?
A. 9.09 x 10
^{-8}
N
B. 1.1 x 10
^{-3}
N
C. 909 N
D. 4545 N
E. 1.1 x 10
^{7}
N
37. A place of zero displacement on a standing wave is called
A. an antinode.
B. a node.
C. the amplitude.
D. the wavenumber.
E. an harmonic.
38. Absolute zero is best described as that temperature at which
A. water freezes at standard pressure.
B. water is at its triple point.
C. the molecules of a substance have a maximum kinetic energy.
D. the molecules of a substance have a maximum potential energy.
E. the molecules of a substance have minimum kinetic energy.
39. A mass of material exists in its solid form at its melting temperature 10ºC. The following processes then occur to the material:
Process 1: An amount of thermal energy Q is added to the material and ¾ of the material melts.
Process 2: An identical additional amount of thermal energy Q is added to the material and the material is now a liquid at 50ºC.
What is the ratio of the latent heat of fusion to the specific heat of the liquid for this material?
80ºC
60ºC
40ºC
20ºC
E. More information is needed to answer this question.
40. Which is not true of an isochoric process on an enclosed ideal gas in which the pressure decreases?
A. The work done is zero.
B. The internal energy of the gas decreases.
C. The heat is zero.
D. The rms speed of the gas molecules decreases.
E. The gas temperature decreases.
41. For the diagram shown, what is the magnitude of the torque from the applied force as measured from the center of the disk?
Fd sin 30º
Fd tan 30º
Fd sin 90º
Fd sin 120º
Fd cos 120º
42. A solid spherical conductor has charge
+Q
and radius
R
. It is surrounded by a solid spherical shell with charge
-Q
, inner radius
2R
, and outer radius
3R
. Which of the following statements is true for the labeled points in the diagram? Assume these objects are isolated in space and that the electric potential is zero as the distance from the spheres approaches infinity.
Point A is at the center of the inner sphere,
Point B is located at r = R + delta,
Point D is located at r = 3R + delta, and
Point C is located at r = 2R - delta
where delta is an infinitesimal amount and all distances are from the center of the inner sphere.
A. The electric potential has a maximum magnitude at C and the electric field has a maximum magnitude at A.
B. The electric potential has a maximum magnitude at D and the electric field has a maximum magnitude at B.
C. The electric potential at A is zero and the electric field has a maximum magnitude at D.
D. The electric potential at A is zero and the electric field has a maximum magnitude at B.
E. Both the electric potential and electric field achieve a maximum magnitude at B.
43. Which of the following best represents the ray diagram construction for finding the image formed for the virtual object shown? The solid dots on either side of the lens locate the equal magnitude foci of the lens.
44. A person vibrates the end of a string sending transverse waves down the string. If the person then doubles the rate at which he vibrates the string, the speed of the wave
A. doubles and the wavelength is unchanged
B. doubles and the wavelength doubled
C. doubles while the wavelength is halved
D. is unchanged while the wavelength is doubled
E. is unchanged while the wavelength is halved.
45. If the temperature of a material doubles on the Kelvin scale, by how much does the time-rate at which energy is radiated from the material change?
A. It is unchanged
B. It is doubled
C. It is 4 times greater
D. It is 8 times greater
E. It is 16 times greater
46. An ideal gas undergoes a reversible isothermal expansion at T = 300 K. The total change in entropy of the gas is 2.5 J/K. How much work was done by the environment on the gas during this process?
A. -750 J
B. -120 J
C. 120 J
D. 750 J
E. More information is required
to answer this question.
47. Two spaceships travel along paths that are at right angles to each other. Each ship travels at 0.60c where
c
is the speed of light in a vacuum according to a stationary observer. If one of the ships turns on a green laser and aims it at a right angle to the direction of its travel, with what speed does the other speed record the speed of the green light?
A. 0.40 c
B. 0.85 c
C. 1.00 c
D. 1.17 c
E. More information is required
about the direction that
the light is traveling in
order to answer the question.
48. How fast must an observer move so that a stationary object appears to be one-half of its proper length?
A. 0.50 c
B. 0.67 c
C. 0.75 c
D. 0.87 c
E. 0.93 c
49. The ratio
of the deBroglie wavelengths of two non-relativistic particles with masses
m
_{1}
and
m
_{2}
and the same kinetic energy, is equal to
50. A gas undergoes radioactive decay with time constant,
T
. A sample of 10,000 particles is put into a container. After one time constant has passed, the experimenter places another 10,000 particles into the original container. How much time passes from the addition of the particles until the container of gas reaches 10,000 total particles again?
0.313 T
0.405 T
0.500 T
0.693 T
T
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at
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