Question 1

Microscopes are inherently limited by the wavelength of the light used.How much smaller (in order of magnitude) can we "see" using an electron microscope whose electrons have been accelerated through a potential difference of 50 000 V than using red light (500 nm) ?

Accepted Answer

A)  3
B)  4
C)  5
D)  6
E)  14F) B) and E)
G) A) and B)

Question 2

A neutron has a mass of 1.67 *10 - 27 kg.Its de Broglie wavelength is 1.4 *10 - 10 m.What is its kinetic energy (in eV) ?

Accepted Answer

A)  4
B)  0.4
C)  0.04
D)  40
E)  0.08F) A) and D)
G) C) and E)

Question 3

An electron has been accelerated by a potential difference of 100 V.If its position is known to have an uncertainty of 1 nm,what is the percent uncertainty ( Δ\DeltaΔ p/p * 100) of the electron?

Accepted Answer

A)  1%
B)  2%
C)  10%
D)  >>10%
E)  5% F) A) and D)
G) All of the above

Question 4

A wave packet can represent a quantum particle because

Accepted Answer

A)  it has the localized nature of a particle.
B)  the group velocity is identical to the speed of the particle.
C)  the waves that compose the packet can show interference and diffraction.
D)  of all of the above.
E)  of only (a) and (b) above.F) B) and C)
G) A) and E)

Question 5

How much energy is in an 89.7 MHz photon of FM-radiation?

Accepted Answer

A)  2.2 *10-33 J
B)  9.5 *10-27 J
C)  7.4 * 10-42 J
D)  5.9 *10-26 J
E)  3.7 *10-25 JF) A) and B)
G) A) and C)

Question 6

A photon collides with an electron.After the collision the wavelength of the scattered wave at a scattering angle greater than  0∘0 ^ { \circ }0∘  is

Accepted Answer

A)  greater than or equal to the initial wavelength.
B)  equal to the initial wavelength.
C)  less than or equal to the initial wavelength.
D)  greater than the initial wavelength.
E)  less or greater depending on the scattering angle. F) A) and D)
G) All of the above

Question 7

The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV.The light intensity is doubled.Determine the maximum kinetic energy of the photoelectrons (in eV) .

Accepted Answer

A)  4
B)  2
C)    2\sqrt { 2 }2c-2.7,0,-7.17,-2.7,-13.5,-8c-5.8,-5.3,-9.5,-10,-9.5,-14c0,-2,0.3,-3.3,1,-4c1.3,-2.7,23.83,-20.7,67.5,-54c44.2,-33.3,65.8,-50.3,66.5,-51c1.3,-1.3,3,-2,5,-2c4.7,0,8.7,3.3,12,10s173,378,173,378c0.7,0,35.3,-71,104,-213c68.7,-142,137.5,-285,206.5,-429c69,-144,104.5,-217.7,106.5,-221l0 -0c5.3,-9.3,12,-14,20,-14H400000v40H845.2724s-225.272,467,-225.272,467s-235,486,-235,486c-2.7,4.7,-9,7,-19,7c-6,0,-10,-1,-12,-3s-194,-422,-194,-422s-65,47,-65,47zM834 80h400000v40h-400000z'/>​ 
D)  3
E)  16 F) None of the above
G) A) and B)

Question 8

Calculate the ground state energy (in eV) for an electron in a box (an infinite well) having a width of 0.050 nm.

Accepted Answer

A)  10
B)  75
C)  24
D)  150
E)  54F) C) and D)
G) A) and B)

Question 9

Assume the Heisenberg uncertainty principle can take the form  Δ\DeltaΔ E Δ\DeltaΔ t  ≥\ge≥  h/4B.How accurate can the position of an electron be made if its speed is 5 * 106 m/s and if the uncertainty in its energy is 10 eV?

Accepted Answer

A)  7.7 *10 - 18 m
B)  1.3 *10 - 23 m
C)  6.2 * 10 - 15 m
D)  1.6 *10 - 10 m
E)  1.2 *10 - 9 m F) A) and E)
G) C) and D)

Question 10

Quantum tunneling occurs in

Accepted Answer

A)  nuclear fusion.
B)  radioactive decay by emission of alpha particles.
C)  the scanning tunneling microscope.
D)  all of the above.
E)  only (b) and (c) above.F) B) and E)
G) All of the above

Question 11

In an experiment different wavelengths of light,all able to eject photoelectrons,shine on a freshly prepared (oxide-free) zinc surface.Which statement is true?

Accepted Answer

A)  The number of photoelectrons emitted per second is independent of the intensity of the light for all the different wavelengths.
B)  The number of photoelectrons emitted per second is directly proportional to the frequency for all the different wavelengths.
C)  The maximum kinetic energy of the photoelectrons emitted is directly proportional to the frequency for each wavelength present.
D)  The maximum kinetic energy of the photoelectrons has a linear relationship with the frequency for each wavelength present.
E)  The maximum kinetic energy of the photoelectrons is proportional to the intensity of the light and independent of the frequency.F) A) and E)
G) None of the above

Question 12

A stopping potential of 3.2 V is needed for radiation whose wavelength is 200 nm.What is the work function (in eV) of the material?

Accepted Answer

A)  4.0
B)  3.0
C)  5.0
D)  6.0
E)  2.0F) B) and D)
G) A) and B)

Question 13

A solid state pulsed laser has an energy of 400 mJ per pulse.If its wavelength is 1.06 *10  - 6 m,how many photons are in each pulse?

Accepted Answer

A)  2*1025
B)  2 *1021
C)  3 *1018
D)  6 * 1038
E)  2 * 1018F) A) and E)
G) A) and D)

Question 14

If the interaction of a particle with its environment restricts the particle to a finite region of space,the result is the quantization of ____ of the particle.

Accepted Answer

A)  the momentum
B)  the energy
C)  the velocity
D)  all of the above properties
E)  only properties (a) and (b) F) A) and E)
G) C) and D)

Question 15

Suppose we use optical radiation ($\lambda$= 500 nm)to determine the position of the electron to within the wavelength of the light.What will be the resulting uncertainty in the electron's velocity?

Accepted Answer

The answer of Suppose we use optical radiation ($\lambda$= 500...

Question 16

The wavelength of a 45-kg teenager moving at 5 m/s on a skateboard is about

Accepted Answer

A)  5*10 - 37 m.
B)  3 *10 - 36 m.
C)  7 *10 - 34 m.
D)  0.1 m.
E)  5 m.F) A) and C)
G) A) and D)

Question 17

Assume we can determine the position of a particle within an uncertainty of 0.5 nm.What will be the resulting uncertainty in the particle's momentum (in kg . m/s) ?

Accepted Answer

A)  1.9 *10-25
B)  4.2 *10-25
C)  1.1 * 10-25
D)  1.3 * 10-24
E)  6.6 * 10-25F) A) and B)
G) C) and D)

Question 18

What is the quantum number n of a particle of mass m confined to a one-dimensional box of length L when its energy is 2 h2/mL2?

Accepted Answer

A)  2
B)  8
C)  4
D)  1
E)  16F) C) and E)
G) A) and B)

Question 19

When U(x) is infinitely large elsewhere,the wave function of a particle restricted to the region 0 Δ\DeltaΔ (x) =

Accepted Answer

A)    Asin⁡(nπxL) A \sin \left( \frac { n \pi x } { L } \right) Asin(Lnπx​)   .
B)    Bcos⁡(nπxL) B \cos \left( \frac { n \pi x } { L } \right) Bcos(Lnπx​)   .
C)  Aen   π\piπ  x / L.
D)    Asin⁡(nπxL) +Bcos⁡(nπxL) A \sin \left( \frac { n \pi x } { L } \right)  + B \cos \left( \frac { n \pi x } { L } \right) Asin(Lnπx​) +Bcos(Lnπx​)   .
E)    Asin⁡(nπxL) −Bcos⁡(nπxL) A \sin \left( \frac { n \pi x } { L } \right)  - B \cos \left( \frac { n \pi x } { L } \right) Asin(Lnπx​) −Bcos(Lnπx​)   . F) B) and E)
G) D) and E)

Question 20

Photoelectrons are ejected when monochromatic light shines on a freshly-prepared (oxide-free) sodium surface.In order to obtain the maximum increase in the number of electrons ejected per second,the experimenter needs to

Accepted Answer

A)  increase the frequency of the light.
B)  increase the intensity of the light.
C)  increase the area illuminated by the light.
D)  do all of the above.
E)  do only (b) and (c) above.F) B) and D)
G) B) and C)

Exam 28: Quantum Physics

Photoelectrons are ejected when monochromatic light shines on a freshly-prepared (oxide-free) sodium surface.In order to obtain the maximum increase in the number of electrons ejected per second,the experimenter needs to

Correct AnswerverifiedShow Answer

Calculate the ground state energy (in eV) for an electron in a box (an infinite well) having a width of 0.050 nm.

Correct AnswerverifiedShow Answer

A stopping potential of 3.2 V is needed for radiation whose wavelength is 200 nm.What is the work function (in eV) of the material?

Correct AnswerverifiedShow Answer

A neutron has a mass of 1.67 *10 - 27 kg.Its de Broglie wavelength is 1.4 *10 - 10 m.What is its kinetic energy (in eV) ?

Correct AnswerverifiedShow Answer

An electron has been accelerated by a potential difference of 100 V.If its position is known to have an uncertainty of 1 nm,what is the percent uncertainty ( Δ\DeltaΔ p/p * 100) of the electron?

Correct AnswerverifiedShow Answer

The light intensity incident on a metallic surface produces photoelectrons with a maximum kinetic energy of 2 eV.The light intensity is doubled.Determine the maximum kinetic energy of the photoelectrons (in eV) .

Correct AnswerverifiedShow Answer

Microscopes are inherently limited by the wavelength of the light used.How much smaller (in order of magnitude) can we "see" using an electron microscope whose electrons have been accelerated through a potential difference of 50 000 V than using red light (500 nm) ?

Correct AnswerverifiedShow Answer

What is the quantum number n of a particle of mass m confined to a one-dimensional box of length L when its energy is 2 h2/mL2?

Correct AnswerverifiedShow Answer

A photon collides with an electron.After the collision the wavelength of the scattered wave at a scattering angle greater than 0∘0 ^ { \circ }0∘ is

Correct AnswerverifiedShow Answer

Quantum tunneling occurs in

Correct AnswerverifiedShow Answer

When U(x) is infinitely large elsewhere,the wave function of a particle restricted to the region 0 < x < L where U(x) = 0,may have the form Δ\DeltaΔ (x) =

Correct AnswerverifiedShow Answer

If the interaction of a particle with its environment restricts the particle to a finite region of space,the result is the quantization of ____ of the particle.

Correct AnswerverifiedShow Answer

Assume the Heisenberg uncertainty principle can take the form Δ\DeltaΔ E Δ\DeltaΔ t ≥\ge≥ h/4B.How accurate can the position of an electron be made if its speed is 5 * 106 m/s and if the uncertainty in its energy is 10 eV?

Correct AnswerverifiedShow Answer

How much energy is in an 89.7 MHz photon of FM-radiation?

Correct AnswerverifiedShow Answer

A wave packet can represent a quantum particle because

Correct AnswerverifiedShow Answer

Assume we can determine the position of a particle within an uncertainty of 0.5 nm.What will be the resulting uncertainty in the particle's momentum (in kg . m/s) ?

Correct AnswerverifiedShow Answer

The wavelength of a 45-kg teenager moving at 5 m/s on a skateboard is about

Correct AnswerverifiedShow Answer

Suppose we use optical radiation ( λ\lambdaλ = 500 nm)to determine the position of the electron to within the wavelength of the light.What will be the resulting uncertainty in the electron's velocity?

Correct AnswerverifiedShow Answer

A solid state pulsed laser has an energy of 400 mJ per pulse.If its wavelength is 1.06 *10 - 6 m,how many photons are in each pulse?

Correct AnswerverifiedShow Answer

In an experiment different wavelengths of light,all able to eject photoelectrons,shine on a freshly prepared (oxide-free) zinc surface.Which statement is true?

Correct AnswerverifiedShow Answer

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Correct Answer
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A neutron has a mass of 1.67 10 ^- ²⁷ kg.Its de Broglie wavelength is 1.4 10 ^- ¹⁰ m.What is its kinetic energy (in eV) ?

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An electron has been accelerated by a potential difference of 100 V.If its position is known to have an uncertainty of 1 nm,what is the percent uncertainty ( $\Delta$ p/p * 100) of the electron?

Correct Answer
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Correct Answer
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Correct Answer
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What is the quantum number n of a particle of mass m confined to a one-dimensional box of length L when its energy is 2 h²/mL²?

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A photon collides with an electron.After the collision the wavelength of the scattered wave at a scattering angle greater than $0 ^ { \circ }$ is

Correct Answer
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Correct Answer
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When U(x) is infinitely large elsewhere,the wave function of a particle restricted to the region 0 < x < L where U(x) = 0,may have the form $\Delta$ (x) =

Correct Answer
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Correct Answer
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Assume the Heisenberg uncertainty principle can take the form $\Delta$ E $\Delta$ t $\ge$ h/4B.How accurate can the position of an electron be made if its speed is 5 * 10⁶ m/s and if the uncertainty in its energy is 10 eV?

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Suppose we use optical radiation ( $\lambda$ = 500 nm)to determine the position of the electron to within the wavelength of the light.What will be the resulting uncertainty in the electron's velocity?

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A solid state pulsed laser has an energy of 400 mJ per pulse.If its wavelength is 1.06 *10 ^- ⁶ m,how many photons are in each pulse?

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Correct Answer
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