Passage X Q 125-131 MCAT 4Q 125

Which of the following changes to the circuit will decrease the electric field between the electrodes?A. Increasing L by a factor of 2B. Decreasing L by a factor of 2C. Increasing R by a factor of 2D. Decreasing R by a factor of 2

Passage X Q 125-131 MCAT 4Q 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?

A. It will be 2 times as large

B. It will be approximately equal

C. It will be 1/4 as large

D. It will be 0

Passage X Q 125-131 MCAT 4Q 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?A. The number of electrons ejectedB. PE of each ejected electronC. Magnitude of the electric field between the

electrodesD. Speed of the electrons at the anode

Passage X Q 125-131 MCAT 4Q 128

Which of the following best describes the motion of an electron after it is ejected from the cathode?

A. It is stationary untill collisions propel it toward the anode

B. I moves with constant speed toward the anode

C. It accelerates toward the anode

D. It exits through a side of the vacuum photodiode

Passage X Q 125-131 MCAT 4Q 129

When the current in the circuit described in the passage is 1 X 10 -3 A, what power is dissipated as heat in the resistor?A. 1 X 10-6 WB. 1 X 10-4 WC. 1 X 10-2 WD. 1 X 10-1 W

Passage X Q 125-131 MCAT 4Q 130

Which of the following occurs when electrons are ejected from the cathode?

A. The voltage across the the electrodes reverses polarity

B. The voltage difference between the electrodes increases

C. Current flows through the circuit

D. The total resistance of the circuit increases

Passage X Q 125-131 MCAT 4Q 131

Increasing the frequency of each photon that is directed at the cathode will:A. decrease the number of photons ejectedB. increase the number of photons ejectedC. decrease the speed of the ejected electronsD. increase the speed of the ejected electrons

Passage X Q 125-131 MCAT 4Q Larry’s Question

Increasing the frequency of each photon that is directed at the cathode will:A. decrease the number of electrons ejectedB. increase the number of electrons ejectedC. decrease the speed of the ejected electronsD. increase the speed of the ejected electronsE . Some combination of the above

Passage VII Q 104-108 MCAT 3Q 104

The conversion efficiency of Material B is 0.42 at a frequency of:

A. 3.5 X 10-15Hz

B. 2.8 X 102Hz

C. 2.8 X 1014Hz

D. 3.5 X 1015Hz

Passage VII Q 104-108 MCAT 3Q 105

The purpose of the reflection coating is most likely to:

A. cool the device

B. Warm the device

C. maximize conversion efficiency

D. reduce the magnitude of the current

Passage VII Q 104-108 MCAT 3Q 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:

A. 4 times as large

B. 2 times as large

C. 1/2 as large

D. the same

Passage VII Q 104-108 MCAT 3Q 108

See graphs