Transcript Physics MCAT Review - UND: University of North Dakota

Passage X Q 125-131 MCAT 4
Q 125
Which of the following changes to the circuit
will decrease the electric field between the
electrodes?
A. Increasing L by a factor of 2
B. Decreasing L by a factor of 2
C. Increasing R by a factor of 2
D. Decreasing R by a factor of 2
Passage X Q 125-131 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?
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 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?
A. The number of electrons ejected
B. PE of each ejected electron
C. Magnitude of the electric field between
the electrodes
D. Speed of the electrons at the anode
Passage X Q 125-131 MCAT 4
Q 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 4
Q 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 W
B. 1 X 10-4 W
C. 1 X 10-2 W
D. 1 X 10-1 W
Passage X Q 125-131 MCAT 4
Q 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 4
Q 131
Increasing the frequency of each photon that
is directed at the cathode will:
A. decrease the number of photons ejected
B. increase the number of photons ejected
C. decrease the speed of the ejected
electrons
D. increase the speed of the ejected
electrons
Passage X Q 125-131 MCAT 4
Q Larry’s Question
Increasing the frequency of each photon that
is directed at the cathode will:
A. decrease the number of electrons ejected
B. increase the number of electrons ejected
C. decrease the speed of the ejected
electrons
D. increase the speed of the ejected
electrons
E. Some combination of the above
Passage VII Q 104-108 MCAT 3
Q 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 3
Q 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 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:
A. 4 times as large
B. 2 times as large
C. 1/2 as large
D. the same
Passage VII Q 104-108 MCAT 3
Q 108
See graphs