Question 1

If the threshold wavelength to dislodge electrons from a metal is 373. nm, what is the work function?

Accepted Answer

The answer of If the threshold wavelength to dislodge electrons...

Question 2

What is the minimum uncertainty in determining the position of an electron if the speed of the electron is 6000 m/s within an accuracy of 0.004%?

Accepted Answer

A)  0.105 mm 
B)  0.153 mm 
C)  0.241 mm 
D)  0.335 mm 
E)  0.483 mm 
A)  0.105 mm 
B)  0.153 mm 
C)  0.241 mm 
D)  0.335 mm 
E)  0.483 mm

Question 3

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 0.591 nm, what is the wavelength of the scattered photon?

Accepted Answer

A)  0.380 nm 
B)  0 nm 
C)  0.550 nm 
D)  0.591 nm 
E)  0.595 nm 
A)  0.380 nm 
B)  0 nm 
C)  0.550 nm 
D)  0.591 nm 
E)  0.595 nm

Question 4

A photon has energy of 4.20 eV. To what wavelength does this energy correspond?

Accepted Answer

A)  321 nm 
B)  103 nm 
C)  296 nm 
D)  412 nm 
E)  420 nm 
A)  321 nm 
B)  103 nm 
C)  296 nm 
D)  412 nm 
E)  420 nm

Question 5

Which one of the following is correct for the energy of a 620 nm beam of light?

Accepted Answer

A)  1.60 × 10-19 eV 
B)  2.10 × 10-19 J 
C)  3.21 × 10-19 J 
D)  1.60 × 10-18 eV 
E)  3.21 × 10-18 eV 
A)  1.60 × 10-19 eV 
B)  2.10 × 10-19 J 
C)  3.21 × 10-19 J 
D)  1.60 × 10-18 eV 
E)  3.21 × 10-18 eV

Question 6

A proton and an electron are both accelerated to the same final speed. If λp is the de Broglie wavelength of the proton and λe is the de Broglie wavelength of the electron, then

Accepted Answer

A)  λp > λe. 
B)  λp = λe. 
C)  λp e. 
D)  Not enough data to answer this question. 
A)  λp > λe. 
B)  λp = λe. 
C)  λp e. 
D)  Not enough data to answer this question.

Question 7

A 60-W bulb is operating at an efficiency of 6.20%. What is the number of photons per second given off by the bulb assuming the wavelength of light to be 580 nm?

Accepted Answer

A)  5.42 × 1018 photons/s 
B)  10.8 × 1018 photons/s 
C)  16.2 × 1018 photons/s 
D)  21.7 × 1018 photons/s 
E)  25.3 × 1018 photons/s 
A)  5.42 × 1018 photons/s 
B)  10.8 × 1018 photons/s 
C)  16.2 × 1018 photons/s 
D)  21.7 × 1018 photons/s 
E)  25.3 × 1018 photons/s

Question 8

Electrons come in discrete units of well defined mass and charge, but they also have wave properties.

Accepted Answer

A) True 
 B)False

Question 9

An electron determined to be at y = 2.000 ± 0.0010 cm has what minimum uncertainty in velocity?

Accepted Answer

The answer of An electron determined to be at y...

Question 10

What is the uncertainty in determining the momentum of an electron if the speed of the electron is 6000 m/s within an accuracy of 0.004%?

Accepted Answer

A)  1.09 × 10-31 kg∙m/s 
B)  1.31 × 10-31 kg∙m/s 
C)  2.19 × 10-31 kg∙m/s 
D)  3.21 × 10-31 kg∙m/s 
E)  4.38 × 10-31 kg∙m/s 
A)  1.09 × 10-31 kg∙m/s 
B)  1.31 × 10-31 kg∙m/s 
C)  2.19 × 10-31 kg∙m/s 
D)  3.21 × 10-31 kg∙m/s 
E)  4.38 × 10-31 kg∙m/s

Question 11

If the position of an electron is measured very precisely there is an uncertainty in measuring its

Accepted Answer

A)  kinetic energy. 
B)  momentum. 
C)  potential energy. 
D)  thermal energy. 
E)  None of the other answers is correct. 
A)  kinetic energy. 
B)  momentum. 
C)  potential energy. 
D)  thermal energy. 
E)  None of the other answers is correct.

Question 12

A certain crystal has an interatomic spacing of 0.142 nm. If a beam of electrons moving with a speed of 1400 m/s is diffracted from this crystal, what is the de Broglie wavelength of the electron?

Accepted Answer

A)  420 nm 
B)  130 nm 
C)  260 nm 
D)  502 nm 
E)  520 nm 
A)  420 nm 
B)  130 nm 
C)  260 nm 
D)  502 nm 
E)  520 nm

Question 13

What is the wavelength of a photon of energy 2.00 eV?

Accepted Answer

The answer of What is the wavelength of a photon...

Question 14

Through what potential must an electron be accelerated to observe maximum diffraction at 70.0° to the surface of a crystal with 0.334 nm between surface planes?

Accepted Answer

The answer of Through what potential must an electron be...

Question 15

Suppose that the speed of an electron traveling 1.0 km/s is known to an accuracy of 1 part in 105 (i.e., within 0.01%). What is the greatest possible accuracy within which we can determine the position of this electron?

Accepted Answer

Question 16

A metallic surface is illuminated with light of wavelength 400. nm. If the work function for this metal is 2.4 eV, calculate the kinetic energy of the ejected electrons, in electron-volts.

Accepted Answer

The answer of A metallic surface is illuminated with light...

Question 17

Which one of the following equations is correct for the maximum kinetic energy of photoelectrons ejected from a metal?

Accepted Answer

A)  Kmax = hc - Wo 
B)  Kmax = hλ - Wo 
C)  Kmax = hf - Wo 
D)  Kmax = hλ/c - Wo 
E)  None of the other choices is correct. 
A)  Kmax = hc - Wo 
B)  Kmax = hλ - Wo 
C)  Kmax = hf - Wo 
D)  Kmax = hλ/c - Wo 
E)  None of the other choices is correct.

Question 18

A certain crystal has an interatomic spacing of 0.442 nm. A beam of neutrons moving with a speed of 1640 m/s is diffracted from the crystal. What is the de Broglie wavelength of the neutron?

Accepted Answer

A)  0.121 nm 
B)  0 nm 
C)  0.241 nm 
D)  0.484 nm 
E)  0.682 nm 
A)  0.121 nm 
B)  0 nm 
C)  0.241 nm 
D)  0.484 nm 
E)  0.682 nm

Question 19

An ideal blackbody absorbs all of the light that is incident on it.

Accepted Answer

A) True 
 B)False

Question 20

What is the energy, in eV, of a photon of wavelength 550. nm?

Accepted Answer

The answer of What is the energy, in eV, of...

Exam 30: Quantum Physics

If the threshold wavelength to dislodge electrons from a metal is 373. nm, what is the work function?

What is the minimum uncertainty in determining the position of an electron if the speed of the electron is 6000 m/s within an accuracy of 0.004%?

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 0.591 nm, what is the wavelength of the scattered photon?

A photon has energy of 4.20 eV. To what wavelength does this energy correspond?

Which one of the following is correct for the energy of a 620 nm beam of light?

A proton and an electron are both accelerated to the same final speed. If λp is the de Broglie wavelength of the proton and λe is the de Broglie wavelength of the electron, then

A 60-W bulb is operating at an efficiency of 6.20%. What is the number of photons per second given off by the bulb assuming the wavelength of light to be 580 nm?

Electrons come in discrete units of well defined mass and charge, but they also have wave properties.

An electron determined to be at y = 2.000 ± 0.0010 cm has what minimum uncertainty in velocity?

What is the uncertainty in determining the momentum of an electron if the speed of the electron is 6000 m/s within an accuracy of 0.004%?

If the position of an electron is measured very precisely there is an uncertainty in measuring its

A certain crystal has an interatomic spacing of 0.142 nm. If a beam of electrons moving with a speed of 1400 m/s is diffracted from this crystal, what is the de Broglie wavelength of the electron?

What is the wavelength of a photon of energy 2.00 eV?

Through what potential must an electron be accelerated to observe maximum diffraction at 70.0° to the surface of a crystal with 0.334 nm between surface planes?

Suppose that the speed of an electron traveling 1.0 km/s is known to an accuracy of 1 part in 105 (i.e., within 0.01%). What is the greatest possible accuracy within which we can determine the position of this electron?

A metallic surface is illuminated with light of wavelength 400. nm. If the work function for this metal is 2.4 eV, calculate the kinetic energy of the ejected electrons, in electron-volts.

Which one of the following equations is correct for the maximum kinetic energy of photoelectrons ejected from a metal?

A certain crystal has an interatomic spacing of 0.442 nm. A beam of neutrons moving with a speed of 1640 m/s is diffracted from the crystal. What is the de Broglie wavelength of the neutron?

An ideal blackbody absorbs all of the light that is incident on it.

What is the energy, in eV, of a photon of wavelength 550. nm?

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

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

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Filters

A proton and an electron are both accelerated to the same final speed. If λ_p is the de Broglie wavelength of the proton and λ_e is the de Broglie wavelength of the electron, then

Suppose that the speed of an electron traveling 1.0 km/s is known to an accuracy of 1 part in 10⁵ (i.e., within 0.01%). What is the greatest possible accuracy within which we can determine the position of this electron?