AAPT Quiz
PhysicsBowl 2009 (Part 2)
26. For the circuit shown below, when a shorting wire (no resistance) connects the points labeled A and B, which of the numbered light bulbs become brighter?
Assume that all four bulbs are identical and have resistance R.
(A) Bulb 1 only
(B) Bulb 2 only
(C) Bulb 3 only
(D) Bulbs 1 and 3 only
(E) Bulbs 1, 2, and 3
27. A proton moves straight up the plane of this page into a region that has a magnetic field directed to the right. If the particle is undeflected as it passes through this region, in what direction must there be a component of electric field? Ignore gravity.
(A) To the left
(B) Into the page
(C) Out of the page
(D) Down the page
(E) To the right
28. White light shines through ideal filters to produce cyan light. If an ideal pigment appears yellow in white light, what color does the pigment appear in the cyan light?
(A) magenta
(B) yellow
(C) blue
(D) red
(E) green
29. The diagram to the left shows the lowest four energy levels for an electron in a hypothetical atom. The electron is excited to the −1 eV level of the atom and transitions to the lowest energy state by emitting only two photons. Which of the following energies could not belong to either of the photons?
(A) 2 eV
(B) 4 eV
(C) 5 eV
(D) 6 eV
(E) 9 eV
30. In terms of the seven fundamental SI units in the MKS system, the Ohm is written as
31. A car moves to the right along a one-dimensional track for total time T in two parts.
Part One: The car maintains constant non-zero speed V for the first ¾ of the total time.
Part Two: The car accelerates uniformly to rest during the last ¼ of the total time.
What is the ratio of the distance traveled during Part One of the trip to the distance traveled during Part Two of the trip?
(A) 6 : 1
(B) 3 : 2
(C) The values of V and T are required to answer the question.
(D) 4 : 3
(E) 8 : 3
32. A cube of unknown material and uniform density floats in a container of water with 60% of its volume submerged. If this same cube were placed in a container of oil with density = 800 kg/m
^{3}
, what portion of the cube’s volume would be submerged while floating?
(A) 33 %
(B) 50 %
(C) 58 %
(D) 67 %
(E) 75 %
33. An ideal gas undergoes an isobaric expansion followed by an isochoric cooling. Which of the following statements must be true after the completion of these processes?
(A) The final pressure is less than the original pressure.
(B) The final volume is less than the original volume.
(C) The final temperature is less than the original temperature.
(D) The total quantity of heat, Q , associated with these processes is positive.
(E) The internal energy of the gas is unchanged.
34. The diagram below shows the path taken by a monochromatic light ray traveling through three media.
The symbols v
_{1}
, λ
_{1}
, and f
_{1}
represent the speed, wavelength, and frequency of the light in Medium 1, respectively. Which of the following relationships for the light in the three media is true?
λ
_{1 }
< λ
_{3 }
< λ
_{2}
v
_{2}
< v
_{3}
< v
_{1}
f
_{2}
< f
_{1}
< f
_{3}
v
_{3}
< v
_{1}
< v
_{2}
λ
_{2 }
<
_{ }
λ
_{1 }
< λ
_{3}
35. A piece of an ideal fluid is marked as it moves along a horizontal streamline through a pipe, as shown in the figure. In Region I, the speed of the fluid on the streamline is V. The cylindrical, horizontal pipe narrows so that the radius of the pipe in Region II is half of what it was in Region I.
What is the speed of the marked fluid when it is in Region II?
(A) 4V
(B) 2V
(C) V
(D) V/2
(E) V/4
36. For the RC circuit shown, the resistance is R = 10.0
Ω
, the capacitance is C = 5.0 F and the battery has voltage = 12 volts . The capacitor is initially uncharged when the switch S is closed at time t = 0 . At some time later, the current in the circuit is 0.50 A.
What is the magnitude of the voltage across the capacitor at that moment?
(A) 0 volts
(B) 5 volts
(C) 6 volts
(D) 7 volts
(E) 12 volts
37. For the figure shown, the variable resistance in the circuit on the left is increased at a constant rate. What is the direction of the magnetic field at the point P at the center of the left-hand circuit and in what direction is the conventional current through the resistor in the right-hand circuit?
(A)
(B)
(C)
(D)
(E)
38. A small object of mass M and charge Q is connected to an insulating massless string in a vacuum on Earth. A uniform electric field exists throughout the region of the vacuum as indicated. The mass remains in static equilibrium at an angle of θ with the vertical as shown in the figure.
When the string is cut, which of the illustrated paths best indicates the trajectory of the mass?
(A)
(B)
(C)
(D)
(E)
39. For the compound machine comprised of the inclined plane and pulley shown, a 75.0 N force is required to slide a box with mass M = 10.0 kg up the incline at a constant speed.
What is the efficiency of this compound machine?
(A) 1/3
(B) 3/8
(C) 1/2
(D) 2/3
(E) 3/4
40. A uniform solid cylinder of mass M = 2.00 kg and radius R = 10.0 cm is connected about an axis through the center of the cylinder to a horizontal spring with spring constant 4.00 N/m.
The cylinder is pulled back, stretching the spring 1.00 m from equilibrium. When released, the cylinder rolls without slipping. What is the speed of the center of the cylinder when it returns to equilibrium?
(A) 0.577 m/sec
(B) 1.00 m/sec
(C) 1.15 m/sec
(D) 1.22 m/sec
(E) 1.41 m/sec
IMPORTANT: All Division 01 students STOP HERE. Your last answer should be number 40. Numbers 41-50 should remain blank for Division 01 students.
All Division 02 students continue to Questions 41 – 50.
41. For the circuits shown below, which will take the least time to charge the capacitor(s) to 90% of the full charge? All batteries are ideal and identical with emf ξ, all resistors are identical with resistance R, and all capacitors are identical with capacitance C and are initially uncharged.
42. A uniform, solid disk with mass M and radius R is rotating on a fixed, frictionless platform with constant angular speed ω
_{o}
about a fixed axis through its center. A second uniform solid disk of mass 2M and radius 2
R is placed from rest directly on top of the first disk so that the centers of the disks line up. When equilibrium is established, the disks are spinning at the same rate. What is the angular speed of the disks at equilibrium?
43. A real object is located in front of a convex lens at a distance greater than the focal length of the lens. What type of image is formed and what is true of the image’s size compared to that of the object?
(A)
(B)
(C)
(D)
(E)
44. In an ideal LC circuit, what is the time difference between all of the energy in the circuit being stored in the inductor and all of the energy being stored in the capacitor?
(A) No time difference
(B) One-eighth of a period of oscillation
(C) One-quarter of a period of oscillation
(D) One-half of a period of oscillation
(E) After one full period of oscillation has passed
45. In neutron decay, the process is written as
necessary to have conservation of momentum and energy. Who postulated the existence of neutrinos?
(A) Pauli
(B) Dirac
(C) de Broglie
(D) Heisenberg
(E) Einstein
46. Monochromatic light is incident on a slide containing six infinitely thin, equally spaced slits as shown in the figure. The resulting interference pattern on a distant screen reveals a place of total destructive interference. Of the following, what must be the phase difference (in radians) between the electric fields from each of the adjacent slits for this location on the screen?
(A) 0
(B)
π/12
(C)
π/6
(D)
π/3
(E)
π/2
47. A spatially uniform electric field is constrained within the circular region of radius R as shown. The field is directed out of the plane of the page and its strength is increasing uniformly in time.
What is the direction of the force on the proton in the figure if the proton is moving to the right at the instant shown? Ignore gravity.
(A) No Force
(B) Up
(C) Down
(D) Out of the page
(E) Into the page
Questions 48 – 49 deal with the following information:
An electromagnetic wave has an electric field given by the expression (in Cartesian coordinates):
48. What is the direction of the energy flow for the wave?
(A) − x
(B) + x
(C) − y
(D) + y
(E) + z
49. What is the direction of the magnetic field at time t = 0 and position x = 0?
(A) − x
(B) + x
(C) − y
(D) + y
(E) + z
50. What is the magnitude of the linear momentum (in units of kg ⋅m/sec) of an electron moving in a
straight line if it has 3.2×10
^{−13}
J of kinetic energy?
(A) 0
(B) 2.6×10
^{−22}
(C) 7.6×10
^{−22}
(D) 1.3×10
^{−21}
(E) 1.9×10
^{−12}
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