If a monochromatic light beam with quantum energy value of 1.6 eV incident upon a photocell where the work function of the target metal is 0.9 eV, what is the maximum kinetic energy of ejected electrons?
a. 2.5 eV
b. 1.8 eV
c. 0.7 eV
d. 3.2 eV
e. 1.3 eV
[Ques. 2] Blue light will not eject electrons from a certain metal; however, which one of the following may possibly eject electrons from that metal?
a. infrared
b. ultraviolet
c. red
d. green
[Ques. 3] If a blackbody is at 2650 C, what will be the peak wavelength emitted? Wien's displacement constant b = 2.898 103 mK.
a. 1.09 m
b. 0.34 m
c. 0.99 m
d. 9.9 m
e. 0.11 m
[Ques. 4] What is the surface temperature of a distant star (which emits light as if it were a blackbody) where the peak wavelength is 422 nm? (Hint: The surface of the human body at 35C has a peak wavelength of 9.41 m). (1 nm = 109 m = 103 m)
a. 12,900 K
b. 13,800 K
c. 6870 K
d. 13,700 K
e. 2290 K
[Ques. 5] If a quantum of radiation has an energy of 2.10 keV, what is its wavelength? (h = 6.63 1034 Js, 1 eV = 1.60 1019 J, c = 3.00 108 m/s, and 1 nm = 109 m)
a. 0.95 nm
b. 197 nm
c. 0.59 nm
d. 1.24 nm
e. 0.14 nm
[Ques. 6] A quantum of radiation has an energy of 1.5 keV. What is its frequency? (h = 6.63 1034 Js and 1 eV = 1.60 1019 J)
a. 3.6E+14 Hz
b. 3.6E+17 Hz
c. 2.3E+17 Hz
d. 2.4E+18 Hz
e. 1.4E+17 Hz
[Ques. 7] The ultraviolet catastrophe predicts that:
a. all objects should radiate extreme amounts of ultraviolet light.
b. as an object gets hotter its light will change from dull red to blue white.
c. a black body can absorb an infinite amount of radiation if the radiation is in the ultraviolet region.
d. the radiated energy approaches zero as the wavelength approaches zero.
[Ques. 8] Classical theories predict that most of the energy from a blackbody should be radiated:
a. as thermal radiation in the infrared region.
b. at the wavelength given by Wien's displacement law.
c. as ultraviolet light.
d. a blackbody should not radiate.
[Ques. 9] According to Wien's displacement law, if the absolute temperature of a radiating blackbody is tripled, then the peak wavelength emitted will change by what factor?
a. 1/3
b. 1
c. 3
d. 9
[Ques. 10] As the temperature of a radiation emitting blackbody becomes higher, what happens to the peak wavelength of the radiation?
a. increases
b. decreases
c. remains constant
d. is directly proportional to temperature
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