 AAPT Quiz 2008 Physics Quiz Bowl (Part 2)
26. If the principal quantum number of an electron is n = 4, how many possible values of the orbital magnetic quantum number ml are there for this electron?
27. A tube of length L1 is open at both ends. A second tube of length L2 is closed at one end and open at the other end. This second tube resonates at the same fundamental frequency as the first tube. What is the value of L2?
28. A diverging lens produces an image of a real object. This image is

29. A strong bar magnet is held very close to the opening of a solenoid as shown in the diagram. As the magnet is moved away from the solenoid at constant speed, what is the direction of conventional current through the resistor shown and what is the direction of the force on the magnet because of the induced current? 30. A light beam passes through the air and strikes the surface of a plastic block. Which pair of statements correctly describes the phase changes for the reflected wave and the transmitted wave? 31. For the circuit shown, ξ = 6.0 V, R1 = 7.0Ω, R2 = 3.0Ω , R3 = 6.0Ω , and R4 = 12.0Ω . After operating for a long time, equilibrium is established. What is the voltage across the capacitor at equilibrium?
32. On February 20, 2008, there was a total lunar eclipse. What was the phase of the Moon during the eclipse?

Questions 33 and 34 refer to the following scenario:

Two point charges are fixed on the x-axis in otherwise empty space as shown below. 33. In which Region(s) is there a place on the x-axis (aside from infinity) at which the electric potential is equal to zero?
34. In which Region(s) is there a place on the x-axis (aside from infinity) at which the electric field is equal to zero?

35. Astronauts on the Moon perform an experiment with a simple pendulum that is released from the horizontal position at rest. At the moment shown in the diagram with 0° < θ < 90°, the total acceleration of the mass may be directed in which of the following ways? 36. An electron moves in the plane of the page through two regions of space along the dotted-line trajectory shown in the figure. There is a uniform electric field in Region I directed into the plane of the page (as shown). There is no electric field in Region II. What is a necessary direction of the magnetic field in regions I and II? (Ignore gravitational forces.) 37. A uniform meter stick has a 45.0 g mass placed at the 20 cm mark as shown in the figure. If a pivot is placed at the 42.5 cm mark and the meter stick remains horizontal in static equilibrium, what is the mass of the meter stick? 38. A 1200 kg satellite orbits Planet X in a circular orbit with a constant speed of 5.00 103 m/sec. The radius of orbit is 7.50 107 m. What is the magnitude of the gravitational force exerted on the satellite by Planet X?
39. An ideal gas is enclosed in a container. The volume of the container is reduced to half the original volume at constant temperature. According to kinetic theory, what is the best explanation for the increase in pressure created by the gas?

40. A point particle of mass m collides with a thin rod pivoted at one end. The rod has mass M = 2m, length L, and moment of inertia I = 1/3 ML2 . The particle moves horizontally with speed V when it hits the bottom of the rod and sticks to it. What is the speed of the particle immediately after collision?
IMPORTANT: All Division I students STOP HERE.
Your last answer should be number 40. Numbers 41-50 should remain blank for Division I students.
All Division II students continue to Questions 41 – 50.

41. The circuit shown has been operating for a long time. The instant after the switch in the circuit labeled S is opened, what is the voltage across the inductor VL and which labeled point (A or B) of the inductor is at a higher potential? Take R1  = 4.0Ω, R2  = 8.0Ω, and L = 2.5 H. 42. A parallel-plate capacitor is connected to a battery. Without disconnecting the capacitor, a student pulls the capacitor’s plates apart so that the plate separation doubles. As a result of this action, what happens to the voltage across the capacitor and the energy stored by the capacitor?

43. Unpolarized light of intensity I0 enters a polarizer-analyzer system in which the angle between the transmission axes of the polarizer and analyzer is 30º. What is the intensity of the light leaving the analyzer?
44. A mole of a monatomic ideal gas has pressure P, volume V, and temperature T. Which of the following processes would result in the greatest amount of energy added to the gas from heat?

45. Electron #1 moves with speed 0.30c where c is the speed of light. Electron #2 moves with speed 0.60c . What is the ratio of the kinetic energy of electron #2 to electron #1?
46. A traveling wave has the form y(x,t) = 3.0sin(2.5 x − 5.0t) where all quantities given are in MKS units, x is position, and t represents time. What is the period of the wave (in seconds)?
47. A radioactive sample decays with a half-life of 2.0 yr . Approximately how much time must pass so that only 31 of the original sample remains?
48. A block of mass M on a horizontal surface is connected to the end of a massless spring of spring constant k. The block is pulled a distance x from equilibrium and when released from rest, the block moves toward equilibrium. What minimum coefficient of kinetic friction between the surface and the block would prevent the block from returning to equilibrium with non-zero speed?
49. A circuit consists of a resistor, capacitor, and inductor connected in series to an AC source. As the source frequency increases, the current in the circuit decreases. Which statement about the circuit is NOT correct as the source frequency increases?

50. An infinitely long solenoid passes through the circuit as shown. The magnetic field of the solenoid, directed into the plane of the page, is weakening which produces a constant emf of magnitude ξ for a closed loop around the outside of the solenoid. Once equilibrium is established in this circuit, what is the voltage across the switch S?