Question 1

The uncertainty in position of an electron in a certain state is 5 * 10-10 m. The uncertainty in its momentum could 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)  any 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)  any of the above 
E)  none of the above D

Question 2

The frequency of light beam A is twice that of light beam B. The ratio EA/EB of photon energies 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 D

Question 3

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 4

The units of the Planck constant h are those of:

Accepted Answer

A)  energy 
B)  power 
C)  momentum 
D)  angular momentum 
E)  frequency 
A)  energy 
B)  power 
C)  momentum 
D)  angular momentum 
E)  frequency

Question 5

Which of the following electromagnetic radiations has photons with the greatest momentum?

Accepted Answer

A)  blue light 
B)  yellow light 
C)  x rays 
D)  radio waves 
E)  microwaves 
A)  blue light 
B)  yellow light 
C)  x rays 
D)  radio waves 
E)  microwaves

Question 6

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L. The reflection coefficient R:

Accepted Answer

A)  is always equal to zero 
B)  is always equal to 1 
C)  does not depend on E - Epot 
D)  is, in general, not equal to zero 
E)  is equal to T + 1 where T is the transmission coefficient 
A)  is always equal to zero 
B)  is always equal to 1 
C)  does not depend on E - Epot 
D)  is, in general, not equal to zero 
E)  is equal to T + 1 where T is the transmission coefficient

Question 7

Of the following which is the best evidence for the wave nature of matter?

Accepted Answer

A)  The photoelectric effect 
B)  The Compton effect 
C)  The spectral radiancy of cavity radiation 
D)  The relationship between momentum and energy for an electron 
E)  The reflection of electrons by crystals 
A)  The photoelectric effect 
B)  The Compton effect 
C)  The spectral radiancy of cavity radiation 
D)  The relationship between momentum and energy for an electron 
E)  The reflection of electrons by crystals

Question 8

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)  0 
A)  0.80 
B)  0.60 
C)  0.50 
D)  0.20 
E)  0

Question 9

Which of the following electromagnetic radiations has photons with the greatest energy?

Accepted Answer

A)  blue light 
B)  yellow light 
C)  x rays 
D)  radio waves 
E)  microwaves 
A)  blue light 
B)  yellow light 
C)  x rays 
D)  radio waves 
E)  microwaves

Question 10

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

Question 11

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 12

In Compton scattering from stationary electrons the largest change in wavelength that can occur is:

Accepted Answer

A)  2.43 * 10-15 m 
B)  2.43 * 10-12 m 
C)  2.43 * 10-9 m 
D)  dependent on the frequency of the incident light 
E)  dependent on the work function 
A)  2.43 * 10-15 m 
B)  2.43 * 10-12 m 
C)  2.43 * 10-9 m 
D)  dependent on the frequency of the incident light 
E)  dependent on the work function

Question 13

Consider the following three particles:   Rank them according to the wavelengths of their matter waves, least to greatest.

Accepted Answer

A)  1, 2, 3 
B)  3, 2, 1 
C)  2, 3, 1 
D)  1, 3, 2 
E)  1, then 2 and 3 tied 
A)  1, 2, 3 
B)  3, 2, 1 
C)  2, 3, 1 
D)  1, 3, 2 
E)  1, then 2 and 3 tied

Question 14

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 15

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 magnitude 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 magnitude of its wave function 
D)  the wavelength of its wave function 
E)  the square of the magnitude of its wave function

Question 16

Electromagnetic radiation with a wavelength of 3.5 *10-12 m is scattered from stationary electrons and photons that have been scattered through 50 $\degree$are detected. An electron from which one of these photons was scattered receives an energy of:

Accepted Answer

A)  0 J 
B)  1.1 * 10-14 J 
C)  1.9 *10-14 J 
D)  2.3 * 10-14 J 
E)  1.3 *10-13 J 
A)  0 J 
B)  1.1 * 10-14 J 
C)  1.9 *10-14 J 
D)  2.3 * 10-14 J 
E)  1.3 *10-13 J

Question 17

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:

Accepted Answer

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

Question 18

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

Question 19

The frequency and wavelength of the matter wave associated with a 10-eV free electron are:

Accepted Answer

A)  1.5 * 1034 Hz, 3.9 * 10-10 m 
B)  1.5*1034 Hz, 1.3 *10-34 m 
C)  2.4 * 1015 Hz, 1.2 *10-9 m 
D)  2.4 * 1015 Hz, 3.9 *10-10 m 
E)  4.8* 1015 Hz, 1.9*10-10 m 
A)  1.5 * 1034 Hz, 3.9 * 10-10 m 
B)  1.5*1034 Hz, 1.3 *10-34 m 
C)  2.4 * 1015 Hz, 1.2 *10-9 m 
D)  2.4 * 1015 Hz, 3.9 *10-10 m 
E)  4.8* 1015 Hz, 1.9*10-10 m

Question 20

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *1013 m - 3. The intensity of the beam is:

Accepted Answer

A)  6.8 *10 - 6 W/m2 
B)  3.2 * 102 W/m2  
C)  1.0 * 103 W/m2 
D)  2.0 *103 W/m2 
E)  4.0 * 103 W/m2 
A)  6.8 *10 - 6 W/m2 
B)  3.2 * 102 W/m2  
C)  1.0 * 103 W/m2 
D)  2.0 *103 W/m2 
E)  4.0 * 103 W/m2

Exam 38: Photons and Matter Waves

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

The frequency of light beam A is twice that of light beam B. The ratio EA/EB of photon energies 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 units of the Planck constant h are those of:

Which of the following electromagnetic radiations has photons with the greatest momentum?

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L. The reflection coefficient R:

Of the following which is the best evidence for the wave nature of matter?

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

Which of the following electromagnetic radiations has photons with the greatest energy?

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

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

In Compton scattering from stationary electrons the largest change in wavelength that can occur is:

Consider the following three particles: Rank them according to the wavelengths of their matter waves, least to greatest.

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

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

Electromagnetic radiation with a wavelength of 3.5 *10-12 m is scattered from stationary electrons and photons that have been scattered through 50 °\degree° are detected. An electron from which one of these photons was scattered receives an energy of:

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

The frequency and wavelength of the matter wave associated with a 10-eV free electron are:

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *1013 m - 3. The intensity of the beam is:

Measurement

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Vector

Motion in Two and Three Dimensions

Force and Motion I

Force and Motion II

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

Rolling, Torque, and Angular Momentum

Equilibrium and Elasticity

Gravitation

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The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

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Circuits

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Magnetic Fields Due to Currents

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Electromagnetic Oscillations and Alternating Current

Maxwells Equations; Magnetism of Matter

Electromagnetic Waves

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Interference

Diffraction

Relativity

More About Matter Waves

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Energy From the Nucleus

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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 could be

The frequency of light beam A is twice that of light beam B. The ratio E_A/E_B of photon energies is:

An electron with energy E is incident upon a potential energy barrier of height E_pot < E and thickness L. The reflection coefficient R:

Electromagnetic radiation with a wavelength of 3.5 *10^-12 m is scattered from stationary electrons and photons that have been scattered through 50 $\degree$ are detected. An electron from which one of these photons was scattered receives an energy of:

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:

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7 *10¹³ m ^- ³. The intensity of the beam is: