1. Passage X Q MCAT 4
Q 125 Which of the following changes to the circuit will decrease the electric field between the electrodes?
. Increasing L by a factor of 2
. Decreasing L by a factor of 2
. Increasing R by a factor of 2
. Decreasing R by a factor of 2

2. Passage X Q MCAT 4
Q 126 An electron is ejected from the cathode by a photon with an energy slightly greater than the work function of the cathode. How will the final KE of the electron upon reaching the anode compare to its initial PE immediately after it has been ejected?
. It will be 2 times as large
. It will be approximately equal
. It will be 1/4 as large
. It will be 0

3. Passage X Q MCAT 4
Q 127 When the number of photons incident on the cathode with energies above the value of the work function increases, which of the following quantities also increases?
. The number of electrons ejected
. PE of each ejected electron
. Magnitude of the electric field between the electrodes
. Speed of the electrons at the anode

4. Passage X Q MCAT 4
Q 128 Which of the following best describes the motion of an electron after it is ejected from the cathode?
. It is stationary untill collisions propel it toward the anode
. I moves with constant speed toward the anode
. It accelerates toward the anode
. It exits through a side of the vacuum photodiode

5. Passage X Q MCAT 4
Q 129 When the current in the circuit described in the passage is 1 X A, what power is dissipated as heat in the resistor?
. 1 X 10-6 W
. 1 X 10-4 W
. 1 X 10-2 W
. 1 X 10-1 W

6. Passage X Q MCAT 4
Q 130 Which of the following occurs when electrons are ejected from the cathode?
. The voltage across the the electrodes reverses polarity
. The voltage difference between the electrodes increases
. Current flows through the circuit
. The total resistance of the circuit increases

7. Passage X Q MCAT 4
Q 131 Increasing the frequency of each photon that is directed at the cathode will:
. decrease the number of photons ejected
. increase the number of photons ejected
. decrease the speed of the ejected electrons
. increase the speed of the ejected electrons

8. Passage X Q MCAT 4
Q Larry’s Question Increasing the frequency of each photon that is directed at the cathode will:
. decrease the number of electrons ejected
. increase the number of electrons ejected
. decrease the speed of the ejected electrons
. increase the speed of the ejected electrons
. Some combination of the above

9. Passage VII Q MCAT 3
Q 104 The conversion efficiency of Material B is 0.42 at a frequency of:
. 3.5 X 10-15Hz
X 102Hz
X 1014Hz
X 1015Hz

10. Passage VII Q MCAT 3
Q 105 The purpose of the reflection coating is most likely to:
. cool the device
. Warm the device
. maximize conversion efficiency
. reduce the magnitude of the current

11. Passage VII Q MCAT 3
Q 106 Suppose that 2 identical photoelectric devices are connected to the same electrical circuit in parallel with each other. Compared to the voltage generated by a single device, the total voltage supplied to the circuit by the parallel devices will be:
. 4 times as large
. 2 times as large
. 1/2 as large
. the same

12. Passage VII Q MCAT 3
Q 108 See graphs