Phys 214 Final
Fall 2004
Form A
50/3
1.
A photoelectric experiment is performed with monochromatic light. In order to increase the
maximum kinetic energy of escaping electrons, we should:
A.
increase the intensity of the light falling on the photoelectric material.
B.
increase the frequency of the light falling on the photoelectric material.
C.
increase the work function of the photoelectric material.
D.
either
of A. or C.
E.
either
of B. or C.
50/4
2.
A metal surface is illuminated by light of wavelength 310 nm. If the work function of the metal is
2.46 eV, what is the maximum kinetic energy of emitted photoelectrons? (For convenience, note
that a photon of wavelength 1240 nm has an energy of 1 eV.)
A.
1.46 eV
1.54 eV
C.
2.54 eV
D.
4 eV
6.46 eV
52/3
3.
When you throw a baseball through an open window, it does not "diffract" because:
A.
It has an extremely large de Broglie wavelength.
It has an extremely small de Broglie wavelength.
C.
It is smaller than the window.
D.
There is a very large uncertainty in its momentum.
None of the above.
53/3
4.
A free electron and a free proton have the same kinetic energy.
This means that, compared to the
matter wave associated with the proton the matter wave associated with the electron has:
A.
a shorter wavelength and a greater frequency.
a longer wavelength and a greater frequency.
C.
a shorter wavelength and the same frequency.
D.
a longer wavelength and the same frequency.
a shorter wavelength and a smaller frequency.
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View Full DocumentPhys 214 Final
Fall 2004
Form A
56/1
5.
The probability that an electron of energy
E
tunnels through a certain barrier is 0.90. If the width
of the potential barrier is doubled, but its height is kept the same, what is now the probability that
an electron of energy
E
can tunnel through this barrier?
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 Energy, Kinetic Energy, Light

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