Exam Version A
h = 6.63 x 10 -34 J sec
c = 3 x 108 m/sec
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) The work function of a particular substance is 2.54 x 10 -19 J. What is the photoelectric cutoff wavelength
for this material?
A) 916 nm
B) 783 nm
C) 509 nm
D) 650 nm
2) What is the velocity of an electron (mass = 9.1 x 10-31 kg) with a de Broglie wavelength of 4.03 mm?
A) 181 m/s
B) 226 m/s
C) 155 m/s
D) 132 m/s
3) An electron (mass = 9.1 x 10-31 kg) is trapped somewhere in a molecule which is 7.69 nm long. Calculate
the minimum kinetic energy of the electron.
A) 280 meV
B) 160 meV
C) 200 meV
D) 16 meV
4) A doubly-ionized lithium atom 3Li++ undergoes a state transition from n = 5 to n = 4. The wavelength of
the photon which is emitted is closest to:
A) 650 nm
B) 750 nm
C) 550 nm
D) 450 nm
E) 350 nm
5) A 35.0 pm photon undergoes multiple Compton scattering by stationary electrons until the final
wavelength of the photon is 75.0 pm. The minimum number of times that the photon was scattered is:
A) 11
B) 8
C) 12
D) 9
E) 10
6) An important observation that led Bohr to formulate his model of the hydrogen atom was the fact that
A) neutrons formed a diffraction pattern when scattered from a nickel crystal.
B) the peak of the blackbody radiation moved to shorter wavelengths as the temperature was increased.
C) a low density gas emitted a series of sharp spectral lines.
D) the emission of light by an atom does not appear to conserve energy.
E) electrons were found to have a wave nature.
7) In order for an atom to emit light, it
A) must be in an excited state.
B) must be fluorescent.
C) must be stimulated by external radiation.
D) must be in the gaseous state.
E) must be in the ground state.
8) A major advantage of an electron microscope over a visible light microscope is that the electron microscope
A) operates with much lower intensity.
B) can penetrate opaque samples.
C) can have much better resolution.
D) has much greater magnification.
E) requires no lenses for its operation.
9) Consider an atom with the electron configuration 1s22s22p63s23p6. Which of the following is an accurate
statement concerning this atom?
A) This atom would probably be very inert chemically.
B) This atom has a non-zero angular momentum.
C) This atom is in an excited state.
D) This atom is most likely to give rise to an ion with charge +2e.
E) The atomic number of this atom is Z = 11.
10) A hydrogen atom is in its n = 2 excited state when its electron absorbs 6.4 eV in an interaction with a
photon. What is the energy of the resulting free electron?
A) 3.9 eV
B) 3 eV
C) 4.5 eV
D) 4.1 eV
2
Answer Key
Testname: QUIZ4
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
B
A
B
D
D
C
A
C
A
B