Question 1

What is the energy (in eV)of an optical photon of frequency  
(h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Accepted Answer

A) 2.66 eV 
B) 1.62 eV 
C) 1.94 eV 
D) 3.27 eV 
A) 2.66 eV 
B) 1.62 eV 
C) 1.94 eV 
D) 3.27 eV

Question 2

The lattice spacing of the principal Bragg planes in sodium chloride is 0.282 nm.For what wavelength of x-rays will the first order reflected beam diffract at 55° with respect to the normal to the crystal planes?

Accepted Answer

A) 0.323 nm 
B) 0.530 nm 
C) 0.662 nm 
D) 0.150 nm 
E) 0.462 nm 
A) 0.323 nm 
B) 0.530 nm 
C) 0.662 nm 
D) 0.150 nm 
E) 0.462 nm

Question 3

A laser pulse of duration 25 ms has a total energy of 1.4 J.If the wavelength of this radiation is 567 nm,how many photons are emitted in one pulse? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 4.0 × 1018 
B) 9.9 × 1019 
C) 4.8 × 1019 
D) 1.6 × 1017 
E) 3.2 × 1017 
A) 4.0 × 1018 
B) 9.9 × 1019 
C) 4.8 × 1019 
D) 1.6 × 1017 
E) 3.2 × 1017

Question 4

Two identical metal bars are heated up until they are both glowing.One of them is "red hot" and the other is "blue hot." Which one is hotter,the one that glows red or the one that glows blue?

Accepted Answer

A) the red one 
B) the blue one 
C) We cannot tell without knowing more about the two bars. 
A) the red one 
B) the blue one 
C) We cannot tell without knowing more about the two bars.

Question 5

When light of wavelength 350 nm is incident on a metal surface,the stopping potential of the photoelectrons is 0.500 V.What is the maximum kinetic energy of these electrons? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Accepted Answer

A) 0.500 eV 
B) 3.04 eV 
C) 3.54 eV 
D) 4.12 eV 
A) 0.500 eV 
B) 3.04 eV 
C) 3.54 eV 
D) 4.12 eV

Question 6

What is the wavelength of a 6.32-eV photon? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Accepted Answer

A) 197 nm 
B) 167 nm 
C) 216 nm 
D) 234 nm 
A) 197 nm 
B) 167 nm 
C) 216 nm 
D) 234 nm

Question 7

A photocathode whose work function is 2.9 eV is illuminated with white light that has a continuous wavelength band from 400 nm to 700 nm.What is the range of the wavelength band in this white light illumination for which photoelectrons are not produced? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Accepted Answer

A) 430 nm to 700 nm 
B) 400 nm to 480 nm 
C) 430 nm to 480 nm 
D) 400 nm to 430 nm 
E) 480 nm to 700 nm 
A) 430 nm to 700 nm 
B) 400 nm to 480 nm 
C) 430 nm to 480 nm 
D) 400 nm to 430 nm 
E) 480 nm to 700 nm

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

Electrons emerge from an electron gun with a speed of 2.0 × 106 m/s and then pass through a double-slit apparatus.Interference fringes with spacing of 2.7 mm are detected on a screen far from the double slit.What would the fringe spacing be if the electrons were replaced by neutrons with the same speed? (h = 6.626 × 10-34 J ∙ s,melectron = 9.11 × 10-31 kg,mneutron = 1.675 × 10-27 kg)

Accepted Answer

A) 1.5 μm 
B) 4.9 m 
C) 0.93 nm 
D) 1.2 km 
A) 1.5 μm 
B) 4.9 m 
C) 0.93 nm 
D) 1.2 km

Question 10

What is the surface temperature of a star,if its radiation peak occurs at a frequency of 1.06 × 1015 Hz? (c = 3.00 × 108 m/s,and the constant in Wien's law is 0.00290 m ∙ K)

Accepted Answer

A) 17,000 K 
B) 14,500 K 
C) 19,000 K 
D) 20,400 K 
E) 10,200 K 
A) 17,000 K 
B) 14,500 K 
C) 19,000 K 
D) 20,400 K 
E) 10,200 K

Question 11

Increasing the brightness of a beam of light without changing its color will increase

Accepted Answer

A) the number of photons per second traveling in the beam. 
B) the energy of each photon. 
C) the speed of the photons. 
D) the frequency of the light. 
E) the wavelength of the photons. 
A) the number of photons per second traveling in the beam. 
B) the energy of each photon. 
C) the speed of the photons. 
D) the frequency of the light. 
E) the wavelength of the photons.

Question 12

A laser emits a pulse of light that lasts 10 ns.The light has a wavelength of 690 nm,and each pulse has an energy of 480 mJ.How many photons are emitted in each pulse? (c = 3.0 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 1.7 × 1018 
B) 2.1 ×   
C) 2.6 ×   
D) 3.1 ×   
A) 1.7 × 1018 
B) 2.1 ×   
C) 2.6 ×   
D) 3.1 ×

Question 13

The work function of a particular metal is  
What is the photoelectric cutoff (threshold)wavelength for this metal? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 473 nm 
B) 308 nm 
C) 393 nm 
D) 554 nm 
A) 473 nm 
B) 308 nm 
C) 393 nm 
D) 554 nm

Question 14

Which of the following actions will increase the energy of a photon? (There could be more than one correct choice. )

Accepted Answer

A) Increase its wavelength. 
B) Increase its frequency. 
C) Decrease its wavelength. 
D) Decrease its frequency. 
E) Increase its speed. 
A) Increase its wavelength. 
B) Increase its frequency. 
C) Decrease its wavelength. 
D) Decrease its frequency. 
E) Increase its speed.

Question 15

An 84-kW AM radio station broadcasts at 1000 kHz.How many photons are emitted each second by the transmitting antenna? (h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 1.3 ×   
B) 2.9 ×   
C) 6.3 ×   
D) 1.4 ×   
A) 1.3 ×   
B) 2.9 ×   
C) 6.3 ×   
D) 1.4 ×

Question 16

A person of mass 50 kg has a de Broglie wavelength of 4.4 × 10-36 m while jogging.How fast is she running? (h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 2.0 m/s 
B) 3.0 m/s 
C) 4.0 m/s 
D) 5.0 m/s 
A) 2.0 m/s 
B) 3.0 m/s 
C) 4.0 m/s 
D) 5.0 m/s

Question 17

Light of a given wavelength is used to illuminate the surface of a metal,however,no photoelectrons are emitted.In order to cause electrons to be ejected from the surface of this metal you should

Accepted Answer

A) use light of a longer wavelength. 
B) use light of a shorter wavelength. 
C) use light of the same wavelength but increase its intensity. 
D) use light of the same wavelength but decrease its intensity. 
A) use light of a longer wavelength. 
B) use light of a shorter wavelength. 
C) use light of the same wavelength but increase its intensity. 
D) use light of the same wavelength but decrease its intensity.

Question 18

Electrons are accelerated to a speed of 4.0 ×  
M/s and are then aimed at a double-slit apparatus,where interference fringes are detected.If the electrons were replaced by neutrons,what speed must neutrons have to produce interference fringes with the same fringe spacing as that observed with the electrons? (h = 6.626 × 10-34 J ∙ s,melectron = 9.11 × 10-31 kg,mneutron = 1.675 × 10-27 kg)

Accepted Answer

A) 2.2 × 101 m/s 
B) 7.3 × 107 m/s 
C) 1.7 × 106 m/s 
D) 9.3 × 102 m/s 
A) 2.2 × 101 m/s 
B) 7.3 × 107 m/s 
C) 1.7 × 106 m/s 
D) 9.3 × 102 m/s

Question 19

What is the longest wavelength of electromagnetic radiation that will eject photoelectrons from sodium metal for which the work function is 2.28 eV? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Accepted Answer

A) 580 nm 
B) 499 nm 
C) 633 nm 
D) 668 nm 
E) 545 nm 
A) 580 nm 
B) 499 nm 
C) 633 nm 
D) 668 nm 
E) 545 nm

Question 20

Gamma rays are photons with very high energy.What is the wavelength of a gamma-ray photon with energy 7.7 × 10-13 J? (c = 3.0 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Accepted Answer

A) 2.6 × 10-13 m 
B) 3.9 × 10-13 m 
C) 3.1 × 10-13 m 
D) 3.5 × 10-13 m 
A) 2.6 × 10-13 m 
B) 3.9 × 10-13 m 
C) 3.1 × 10-13 m 
D) 3.5 × 10-13 m

Exam 30: Quantum Physics

What is the energy (in eV)of an optical photon of frequency (h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

The lattice spacing of the principal Bragg planes in sodium chloride is 0.282 nm.For what wavelength of x-rays will the first order reflected beam diffract at 55° with respect to the normal to the crystal planes?

A laser pulse of duration 25 ms has a total energy of 1.4 J.If the wavelength of this radiation is 567 nm,how many photons are emitted in one pulse? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Two identical metal bars are heated up until they are both glowing.One of them is "red hot" and the other is "blue hot." Which one is hotter,the one that glows red or the one that glows blue?

When light of wavelength 350 nm is incident on a metal surface,the stopping potential of the photoelectrons is 0.500 V.What is the maximum kinetic energy of these electrons? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

What is the wavelength of a 6.32-eV photon? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

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

What is the surface temperature of a star,if its radiation peak occurs at a frequency of 1.06 × 1015 Hz? (c = 3.00 × 108 m/s,and the constant in Wien's law is 0.00290 m ∙ K)

Increasing the brightness of a beam of light without changing its color will increase

A laser emits a pulse of light that lasts 10 ns.The light has a wavelength of 690 nm,and each pulse has an energy of 480 mJ.How many photons are emitted in each pulse? (c = 3.0 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

The work function of a particular metal is What is the photoelectric cutoff (threshold)wavelength for this metal? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Which of the following actions will increase the energy of a photon? (There could be more than one correct choice. )

An 84-kW AM radio station broadcasts at 1000 kHz.How many photons are emitted each second by the transmitting antenna? (h = 6.626 × 10-34 J ∙ s)

A person of mass 50 kg has a de Broglie wavelength of 4.4 × 10-36 m while jogging.How fast is she running? (h = 6.626 × 10-34 J ∙ s)

Light of a given wavelength is used to illuminate the surface of a metal,however,no photoelectrons are emitted.In order to cause electrons to be ejected from the surface of this metal you should

What is the longest wavelength of electromagnetic radiation that will eject photoelectrons from sodium metal for which the work function is 2.28 eV? (c = 3.00 × 108 m/s,h = 6.626 × 10-34 J ∙ s,1 eV = 1.60 × 10-19 J)

Gamma rays are photons with very high energy.What is the wavelength of a gamma-ray photon with energy 7.7 × 10-13 J? (c = 3.0 × 108 m/s,h = 6.626 × 10-34 J ∙ s)

Introduction to Physics

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Filters

What is the energy (in eV)of an optical photon of frequency (h = 6.626 × 10^-34 J ∙ s,1 eV = 1.60 × 10^-19 J)

A laser pulse of duration 25 ms has a total energy of 1.4 J.If the wavelength of this radiation is 567 nm,how many photons are emitted in one pulse? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)

When light of wavelength 350 nm is incident on a metal surface,the stopping potential of the photoelectrons is 0.500 V.What is the maximum kinetic energy of these electrons? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s,1 eV = 1.60 × 10^-19 J)

What is the wavelength of a 6.32-eV photon? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s,1 eV = 1.60 × 10^-19J)

What is the surface temperature of a star,if its radiation peak occurs at a frequency of 1.06 × 10¹⁵ Hz? (c = 3.00 × 10⁸ m/s,and the constant in Wien's law is 0.00290 m ∙ K)

A laser emits a pulse of light that lasts 10 ns.The light has a wavelength of 690 nm,and each pulse has an energy of 480 mJ.How many photons are emitted in each pulse? (c = 3.0 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)

The work function of a particular metal is What is the photoelectric cutoff (threshold)wavelength for this metal? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)

An 84-kW AM radio station broadcasts at 1000 kHz.How many photons are emitted each second by the transmitting antenna? (h = 6.626 × 10^-34 J ∙ s)

A person of mass 50 kg has a de Broglie wavelength of 4.4 × 10^-36 m while jogging.How fast is she running? (h = 6.626 × 10^-34 J ∙ s)

What is the longest wavelength of electromagnetic radiation that will eject photoelectrons from sodium metal for which the work function is 2.28 eV? (c = 3.00 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s,1 eV = 1.60 × 10^-¹⁹ J)

Gamma rays are photons with very high energy.What is the wavelength of a gamma-ray photon with energy 7.7 × 10^-13 J? (c = 3.0 × 10⁸ m/s,h = 6.626 × 10^-34 J ∙ s)