(Multiple choice)

(1) 

The quantized character of electromagnetic radiation is revealed by 

(a) The Young double-slit experiment. 

(b) Diffraction of light by a small aperture. 

(c) The photoelectric effect. 

(d) The J. J. Thomson cathode-ray experiment.

(2)

Two monochromatic light sources, A and B, emit the same number of photons per second. The wave length of A is λ_A =400 nm, and that of B is λ_B = 600 nm. The power radiated by source B is 

(a) Equal to that of source A. 

(b) Less than that of source A. 

(c) Greater than that of source A. 

(d) Cannot be compared to that from source A using the available data.

(3) True and False

In the photoelectric effect, 

(a) The current is proportional to the intensity of the incident light. 

(b) The work function of a metal depends on the frequency of the incident light. 

(c) The maximum kinetic energy of electrons emitted varies linearly with the frequency of the incident light. 

(d) The energy of a photon is proportional to its frequency.

(4)

In the photoelectric effect, the number of electrons emitted per second is 

(a) Independent of the light intensity. 

(b) Proportional to the light intensity. 

(c) Proportional to the work function of the emitting surface.

(d) Proportional to the frequency of the light.

(5)

The work function of a surface is ф. The threshold wavelength for emission of photoelectrons from the surface is 

(a) hc/ф. 

(b) ф/hf. 

(c) hf/ф. 

(d) None of the above.

(6) True or false: 

(a) The de Broglie wavelength of an electron varies inversely with its momentum. 

(b) Electrons can be diffracted. 

(c) Neutrons can be diffracted. 

(d) An electron microscope is used to look at electrons.

(7)

If the de Broglie wavelength of an electron and a proton are equal, then 

(a) The velocity of the proton is greater than that of the electron. 

(b) The velocity of the proton and electron are equal. 

(c) The velocity of the proton is less than that of the electron. 

(d) The energy of the proton is greater than that of the electron. 

(e) Both (a) and (d) are correct.

(8)

A proton and an electron have equal kinetic energies. It follows that the de Broglie wavelength of the proton is 

(a) Greater than that of the electron. 

(b) Equal to that of the electron. 

(c) Less than that of the electron.

(9) True or false: 

(a) It is impossible in principle to know precisely the position of an electron. 

(b) A particle that is confined to some region of space cannot have zero energy. 

(c) All phenomena in nature are adequately described by classical wave theory. 

(d) The expectation value of a quantity is the value that you expect to measure.