Question 1

The reflection coefficient R for a certain barrier tunneling problem is 0.80. The corresponding transmission coefficient T is:

Accepted Answer

A)  0.80 
B)  0.60 
C)  0.50 
D)  0.20 
E)  zero 
A)  0.80 
B)  0.60 
C)  0.50 
D)  0.20 
E)  zero D

Question 2

In a photoelectric effect experiment no electrons are ejected if the frequency of the incident light is less than A/h, where h is the Planck constant and A is:

Accepted Answer

A)  the maximum energy needed to eject the least energetic electron 
B)  the minimum energy needed to eject the least energetic electron 
C)  the maximum energy needed to eject the most energetic electron 
D)  the minimum energy needed to eject the most energetic electron 
E)  the intensity of the incident light 
A)  the maximum energy needed to eject the least energetic electron 
B)  the minimum energy needed to eject the least energetic electron 
C)  the maximum energy needed to eject the most energetic electron 
D)  the minimum energy needed to eject the most energetic electron 
E)  the intensity of the incident light D

Question 3

The diagram shows the graphs of the stopping potential as a function of the frequency of the incident light for photoelectric experiments performed on three different materials. Rank the materials according to the values of their work functions, from least to greatest.

Accepted Answer

A)  1, 2, 3 
B)  3, 2, 1 
C)  2, 3, 1 
D)  2, 1, 3 
E)  1, 3, 2 
A)  1, 2, 3 
B)  3, 2, 1 
C)  2, 3, 1 
D)  2, 1, 3 
E)  1, 3, 2 A

Question 4

A free electron and a free proton have the same speed. This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron has:

Accepted Answer

A)  a shorter wavelength and a greater frequency 
B)  a longer wavelength and a greater frequency 
C)  the same wavelength and the same frequency 
D)  the same wavelength and a greater frequency 
E)  a longer wavelength and a smaller frequency 
A)  a shorter wavelength and a greater frequency 
B)  a longer wavelength and a greater frequency 
C)  the same wavelength and the same frequency 
D)  the same wavelength and a greater frequency 
E)  a longer wavelength and a smaller frequency

Question 5

J. J. Thompson's measurement of e/m for electrons provides evidence of the:

Accepted Answer

A)  wave nature of matter 
B)  particle nature of matter 
C)  wave nature of radiation 
D)  particle nature of radiation 
E)  transverse wave nature of light 
A)  wave nature of matter 
B)  particle nature of matter 
C)  wave nature of radiation 
D)  particle nature of radiation 
E)  transverse wave nature of light

Question 6

The uncertainty in position of an electron in a certain state is 5 *10-10 m. The uncertainty in its momentum must be

Accepted Answer

A)  5.0 * 10-24 kg .m/s 
B)  4.0 *10-24 kg .m/s 
C)  3.0 *10-24 kg .m/s 
D)  all of the above 
E)  none of the above 
A)  5.0 * 10-24 kg .m/s 
B)  4.0 *10-24 kg .m/s 
C)  3.0 *10-24 kg .m/s 
D)  all of the above 
E)  none of the above

Question 7

The probability that a particle is in a given small region of space is proportional to:

Accepted Answer

A)  its energy 
B)  its momentum 
C)  the frequency of its wave function 
D)  the wavelength of its wave function 
E)  the square of the magnitude of its wave function 
A)  its energy 
B)  its momentum 
C)  the frequency of its wave function 
D)  the wavelength of its wave function 
E)  the square of the magnitude of its wave function

Question 8

Maxwell's equations are to electric and magnetic fields as __________ equation is to the wave function of the particle.

Accepted Answer

A)  Einstein's 
B)  Fermi's 
C)  Newton's 
D)  Schrodinger's 
E)  Bohr's 
A)  Einstein's 
B)  Fermi's 
C)  Newton's 
D)  Schrodinger's 
E)  Bohr's

Question 9

A non-relativistic free electron has kinetic energy K. If its wavelength doubles, its kinetic energy is:

Accepted Answer

A)  4 K 
B)  2 K 
C)  still K 
D)  K/2 
E)  K/4 
A)  4 K 
B)  2 K 
C)  still K 
D)  K/2 
E)  K/4

Question 10

Consider the following:   The only possible processes are:

Accepted Answer

A)  I 
B)  III 
C)  I and III 
D)  I and IV 
E)  II and IV 
A)  I 
B)  III 
C)  I and III 
D)  I and IV 
E)  II and IV

Question 11

The significance of $\mid$$\Psi$$\mid$2 is:

Accepted Answer

A)  probability 
B)  energy 
C)  probability density 
D)  energy density 
E)  wavelength 
A)  probability 
B)  energy 
C)  probability density 
D)  energy density 
E)  wavelength

Question 12

In a photoelectric effect experiment at a frequency above cut off, the number of electrons ejected is proportional to:

Accepted Answer

A)  their kinetic energy 
B)  their potential energy 
C)  the work function 
D)  the frequency of the incident light 
E)  the number of photons that hit the sample 
A)  their kinetic energy 
B)  their potential energy 
C)  the work function 
D)  the frequency of the incident light 
E)  the number of photons that hit the sample

Question 13

A free electron and a free proton have the same momentum. This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron has:

Accepted Answer

A)  a shorter wavelength and a greater frequency 
B)  a longer wavelength and a greater frequency 
C)  the same wavelength and the same frequency 
D)  the same wavelength and a greater frequency 
E)  the same wavelength and a smaller frequency 
A)  a shorter wavelength and a greater frequency 
B)  a longer wavelength and a greater frequency 
C)  the same wavelength and the same frequency 
D)  the same wavelength and a greater frequency 
E)  the same wavelength and a smaller frequency

Question 14

Of the following, Compton scattering from electrons is most easily observed for:

Accepted Answer

A)  microwaves 
B)  infrared light 
C)  visible light 
D)  ultraviolet light 
E)  x rays 
A)  microwaves 
B)  infrared light 
C)  visible light 
D)  ultraviolet light 
E)  x rays

Question 15

In Compton scattering from stationary electrons the largest change in wavelength occurs when the photon is scattered through:

Accepted Answer

A)  0$\degree$ 
B)  22.5$\degree$ 
C)  45$\degree$ 
D)  90$\degree$ 
E)  180$\degree$ 
A)  0$\degree$ 
B)  22.5$\degree$ 
C)  45$\degree$ 
D)  90$\degree$ 
E)  180$\degree$

Question 16

The wavelength of light beam B is twice the wavelanght of light beam B. The energy of a photom in beam A is:

Accepted Answer

A)  half the energy of photon in beam B 
B)  one-forth the energy of a photon in beam B 
C)  equal to the energy of a photon in beam B 
D)  twice energy of a photon in beam B 
E)  four times the energy of a photon in beam B 
A)  half the energy of photon in beam B 
B)  one-forth the energy of a photon in beam B 
C)  equal to the energy of a photon in beam B 
D)  twice energy of a photon in beam B 
E)  four times the energy of a photon in beam B

Question 17

Which of the following is NOT evidence for the wave nature of matter?

Accepted Answer

A)  The photoelectric effect 
B)  The diffraction pattern obtained when electrons pass through a slit 
C)  Electron tunneling 
D)  The validity of the Heisenberg uncertainty principle 
E)  The interference pattern obtained when electrons pass through a two-slit system 
A)  The photoelectric effect 
B)  The diffraction pattern obtained when electrons pass through a slit 
C)  Electron tunneling 
D)  The validity of the Heisenberg uncertainty principle 
E)  The interference pattern obtained when electrons pass through a two-slit system

Question 18

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *1013 nm-13. The intensity of the beam is:

Accepted Answer

A)  6.7 *10-6 W/m2 
B)  1.0 * 103 W/m2 
C)  2.0 * 103 W/m2 
D)  4.0 *103 W/m2 
E)  3.2 * 102 W/m2 
A)  6.7 *10-6 W/m2 
B)  1.0 * 103 W/m2 
C)  2.0 * 103 W/m2 
D)  4.0 *103 W/m2 
E)  3.2 * 102 W/m2

Question 19

In order to tunnel through a potential barrier a particle must:

Accepted Answer

A)  have energy greater than the barrier height 
B)  have spin 
C)  be massive 
D)  have a wavelength longer than the barrier width 
E)  none of the above 
A)  have energy greater than the barrier height 
B)  have spin 
C)  be massive 
D)  have a wavelength longer than the barrier width 
E)  none of the above

Question 20

A photon in light beam A has twice the energy of a photon in light beam B. The ratio pA/pB of their momenta is:

Accepted Answer

A)  1/2 
B)  1/4 
C)  1 
D)  2 
E)  4 
A)  1/2 
B)  1/4 
C)  1 
D)  2 
E)  4

Exam 38: Photons and Matter Waves

The reflection coefficient R for a certain barrier tunneling problem is 0.80. The corresponding transmission coefficient T is:

In a photoelectric effect experiment no electrons are ejected if the frequency of the incident light is less than A/h, where h is the Planck constant and A is:

The diagram shows the graphs of the stopping potential as a function of the frequency of the incident light for photoelectric experiments performed on three different materials. Rank the materials according to the values of their work functions, from least to greatest.

A free electron and a free proton have the same speed. This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron has:

J. J. Thompson's measurement of e/m for electrons provides evidence of the:

The uncertainty in position of an electron in a certain state is 5 *10-10 m. The uncertainty in its momentum must be

The probability that a particle is in a given small region of space is proportional to:

Maxwell's equations are to electric and magnetic fields as __________ equation is to the wave function of the particle.

A non-relativistic free electron has kinetic energy K. If its wavelength doubles, its kinetic energy is:

Consider the following: The only possible processes are:

The significance of ∣\mid∣Ψ\PsiΨ∣\mid∣ 2 is:

In a photoelectric effect experiment at a frequency above cut off, the number of electrons ejected is proportional to:

A free electron and a free proton have the same momentum. This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron has:

Of the following, Compton scattering from electrons is most easily observed for:

In Compton scattering from stationary electrons the largest change in wavelength occurs when the photon is scattered through:

The wavelength of light beam B is twice the wavelanght of light beam B. The energy of a photom in beam A is:

Which of the following is NOT evidence for the wave nature of matter?

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *1013 nm-13. The intensity of the beam is:

In order to tunnel through a potential barrier a particle must:

A photon in light beam A has twice the energy of a photon in light beam B. The ratio pA/pB of their momenta is:

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The uncertainty in position of an electron in a certain state is 5 *10^-¹⁰ m. The uncertainty in its momentum must be

The significance of $\mid$ $\Psi$ $\mid$ ² is:

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *10¹³ nm^-¹³. The intensity of the beam is:

A photon in light beam A has twice the energy of a photon in light beam B. The ratio p_A/p_B of their momenta is: