Question 1

The Compton effect justifies that light acts as photons.

Accepted Answer

A) True 
 B)False

Question 2

A certain photon after being scattered from a free electron at rest moves at an angle of 120° with respect to the incident direction. If the wavelength of the incident photon is 0.611 nm, what is the kinetic energy of the recoiling electron?

Accepted Answer

A)  1.5 × 10-18 J 
B)  2.1 × 10-18 J 
C)  3.1 × 10-18 J 
D)  4.3 × 10-18 J 
E)  5.2 × 10-18 J 
A)  1.5 × 10-18 J 
B)  2.1 × 10-18 J 
C)  3.1 × 10-18 J 
D)  4.3 × 10-18 J 
E)  5.2 × 10-18 J

Question 3

A crystal diffracted a beam of electrons. The crystal spacing was 0.18 nm and the maximum scattering occurred at 80.° relative to the surface normal. The electrons were directed normally onto the crystal.
(a) What is the wavelength of the electrons?
(b) What potential difference accelerated the electrons?

Accepted Answer

The answer of A crystal diffracted a beam of electrons....

Question 4

The radius of a typical nucleus is about 5.0 × 10-15 m. Assuming this to be the uncertainty in the position of a proton in the nucleus, estimate the uncertainty in the proton's energy (in eV).

Accepted Answer

Question 5

The de Broglie wavelength is inversely proportional to the momentum of the particle.

Accepted Answer

A) True 
 B)False

Question 6

An electron is moving with the speed of 1780 m/s. What is its de Broglie wavelength?

Accepted Answer

A)  409 nm 
B)  302 nm 
C)  205 nm 
D)  420 nm 
E)  502 nm 
A)  409 nm 
B)  302 nm 
C)  205 nm 
D)  420 nm 
E)  502 nm

Question 7

The frequency of a light beam is doubled. Which one of the following is correct for the momentum of the photons in that beam of light?

Accepted Answer

A)  It stays the same. 
B)  It is halved. 
C)  It is doubled. 
D)  It is reduced by one-fourth 
E)  It is quadrupled. 
A)  It stays the same. 
B)  It is halved. 
C)  It is doubled. 
D)  It is reduced by one-fourth 
E)  It is quadrupled.

Question 8

Protons are being accelerated in a particle accelerator. When the speed of the protons is doubled, their de Broglie wavelength will

Accepted Answer

A)  increase by a factor of 4. 
B)  increase by a factor of 2. 
C)  decrease by a factor of 2. 
D)  increase by a factor of   . 
E)  decrease by a factor of   . 
A)  increase by a factor of 4. 
B)  increase by a factor of 2. 
C)  decrease by a factor of 2. 
D)  increase by a factor of   . 
E)  decrease by a factor of   .

Question 9

Which one of the following is the correct expression for the Heisenberg uncertainty principle?

Accepted Answer

A)  ΔpyΔy ≥ h/2π 
B)  ΔpyΔy ≤ h/2π 
C)  Δpy/Δy ≤ h/2π 
D)  Δy/Δpy ≥ h/2π 
E)  None of the other answers is correct. 
A)  ΔpyΔy ≥ h/2π 
B)  ΔpyΔy ≤ h/2π 
C)  Δpy/Δy ≤ h/2π 
D)  Δy/Δpy ≥ h/2π 
E)  None of the other answers is correct.

Question 10

In the spectrum of white light which one of the following colors corresponds to the highest temperature?

Accepted Answer

A)  Yellow 
B)  Violet 
C)  Green 
D)  Red 
E)  Orange 
A)  Yellow 
B)  Violet 
C)  Green 
D)  Red 
E)  Orange

Question 11

A metallic surface has a work function of 2.50 eV. What is the longest wavelength that will eject electrons from the surface of this metal?

Accepted Answer

The answer of A metallic surface has a work function...

Question 12

A beam of white light of a certain frequency is incident on a metal surface. If the work function of this surface is 2.20 eV, what frequency of light would give a maximum kinetic energy of 0.25 eV to the photoelectrons ejected from this surface?

Accepted Answer

A)  2.05 × 1014 Hz 
B)  1.02 × 1014 Hz 
C)  2.50 × 1014 Hz 
D)  3.53 × 1014 Hz 
E)  5.92 × 1014 Hz 
A)  2.05 × 1014 Hz 
B)  1.02 × 1014 Hz 
C)  2.50 × 1014 Hz 
D)  3.53 × 1014 Hz 
E)  5.92 × 1014 Hz

Question 13

Which of the following is the correct equation for the momentum of a photon?

Accepted Answer

A)  p = (hc)/λ 
B)  p = λ/c 
C)  p = (hc)/f 
D)  p = (hf)/c 
E)  p = (hλ)/c 
A)  p = (hc)/λ 
B)  p = λ/c 
C)  p = (hc)/f 
D)  p = (hf)/c 
E)  p = (hλ)/c

Question 14

What is the momentum of a photon of light that has a frequency of 2.8 × 1014 Hz?

Accepted Answer

A)  1.5 × 10-28 kg∙m/s 
B)  2.1 × 10-28 kg∙m/s 
C)  4.4 × 10-28 kg∙m/s 
D)  6.3 × 10-28 kg∙m/s 
E)  6.2 × 10-28 kg∙m/s 
A)  1.5 × 10-28 kg∙m/s 
B)  2.1 × 10-28 kg∙m/s 
C)  4.4 × 10-28 kg∙m/s 
D)  6.3 × 10-28 kg∙m/s 
E)  6.2 × 10-28 kg∙m/s

Question 15

FIGURE 30-1  
-The graph shown in Figure 30-1 is a plot based on student data from their testing of a
photoelectric material.
(a) Determine the cutoff frequency.
(b) Determine the work function.

Accepted Answer

(a)25.× 10

Question 16

The distribution of energy in the blackbody radiation depends upon the material from which the blackbody is constructed.

Accepted Answer

A) True 
 B)False

Question 17

A photon is a particle with positive charge.

Accepted Answer

A) True 
 B)False

Question 18

Mathilda collects photoelectric data in her physics laboratory. She measures a stopping potential of 5.82 volts for radiation of wavelength 100. nm, and 17.99 volts stops 50.0 nm.
(a) What is the work function for the material in eV?
(b) From her data one determines Planck's constant to be what?

Accepted Answer

(a)6.70 eV

Question 19

If the frequency of a photon is halved, what happens to its energy?

Accepted Answer

A)  It is doubled. 
B)  It is halved. 
C)  It is tripled. 
D)  It is quadrupled. 
E)  It is reduced by one-fourth. 
A)  It is doubled. 
B)  It is halved. 
C)  It is tripled. 
D)  It is quadrupled. 
E)  It is reduced by one-fourth.

Question 20

A photon has an energy of 6.60 eV. To what wavelength does this energy correspond?

Accepted Answer

A)  100 nm 
B)  118 nm 
C)  151 nm 
D)  173 nm 
E)  189 nm 
A)  100 nm 
B)  118 nm 
C)  151 nm 
D)  173 nm 
E)  189 nm

Exam 30: Quantum Physics

The Compton effect justifies that light acts as photons.

A certain photon after being scattered from a free electron at rest moves at an angle of 120° with respect to the incident direction. If the wavelength of the incident photon is 0.611 nm, what is the kinetic energy of the recoiling electron?

The radius of a typical nucleus is about 5.0 × 10-15 m. Assuming this to be the uncertainty in the position of a proton in the nucleus, estimate the uncertainty in the proton's energy (in eV).

The de Broglie wavelength is inversely proportional to the momentum of the particle.

An electron is moving with the speed of 1780 m/s. What is its de Broglie wavelength?

The frequency of a light beam is doubled. Which one of the following is correct for the momentum of the photons in that beam of light?

Protons are being accelerated in a particle accelerator. When the speed of the protons is doubled, their de Broglie wavelength will

Which one of the following is the correct expression for the Heisenberg uncertainty principle?

In the spectrum of white light which one of the following colors corresponds to the highest temperature?

A metallic surface has a work function of 2.50 eV. What is the longest wavelength that will eject electrons from the surface of this metal?

A beam of white light of a certain frequency is incident on a metal surface. If the work function of this surface is 2.20 eV, what frequency of light would give a maximum kinetic energy of 0.25 eV to the photoelectrons ejected from this surface?

Which of the following is the correct equation for the momentum of a photon?

What is the momentum of a photon of light that has a frequency of 2.8 × 1014 Hz?

FIGURE 30-1 -The graph shown in Figure 30-1 is a plot based on student data from their testing of a photoelectric material. (a) Determine the cutoff frequency. (b) Determine the work function.

The distribution of energy in the blackbody radiation depends upon the material from which the blackbody is constructed.

A photon is a particle with positive charge.

Mathilda collects photoelectric data in her physics laboratory. She measures a stopping potential of 5.82 volts for radiation of wavelength 100. nm, and 17.99 volts stops 50.0 nm. (a) What is the work function for the material in eV? (b) From her data one determines Planck's constant to be what?

If the frequency of a photon is halved, what happens to its energy?

A photon has an energy of 6.60 eV. To what wavelength does this energy correspond?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic Energy

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric Potential Energy

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

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Physical Optics: Interference and Diffraction

Relativity

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The radius of a typical nucleus is about 5.0 × 10^-15 m. Assuming this to be the uncertainty in the position of a proton in the nucleus, estimate the uncertainty in the proton's energy (in eV).

What is the momentum of a photon of light that has a frequency of 2.8 × 10¹⁴ Hz?