Question 1

Monoenergetic electrons are incident on a single slit barrier.If the energy of each incident electron is increased the central maximum of the diffraction pattern:

Accepted Answer

A) widens 
B) narrows 
C) stays the same width 
D) widens for slow electrons and narrows for fast electrons 
E) narrows for slow electrons and widens for fast electrons 
A) widens 
B) narrows 
C) stays the same width 
D) widens for slow electrons and narrows for fast electrons 
E) narrows for slow electrons and widens for fast electrons

Question 2

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L.If the reflection coefficient R = 0.05,

Accepted Answer

A) the electron has a 0.05% chance of being reflected 
B) the electron has a 5% chance of being reflected 
C) the electron has a 95% chance of being reflected 
D) the electron will be partially reflected and partially transmitted 
E) the electron has no chance of being reflected 
A) the electron has a 0.05% chance of being reflected 
B) the electron has a 5% chance of being reflected 
C) the electron has a 95% chance of being reflected 
D) the electron will be partially reflected and partially transmitted 
E) the electron has no chance of being reflected

Question 3

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 4

A free electron in motion along the x axis has a localized wave function.If it enters a region of space where its potential energy increases,

Accepted Answer

A) its total energy will decrease. 
B) its momentum will increase. 
C) its wave number will increase. 
D) its wavelength will increase. 
E) its kinetic energy will increase. 
A) its total energy will decrease. 
B) its momentum will increase. 
C) its wave number will increase. 
D) its wavelength will increase. 
E) its kinetic energy will increase.

Question 5

Identical particles, each with energy E, are incident on the following four potential energy barriers:   Rank the barriers in terms of the probability that the particles tunnel through them, from least probability to greatest probability.

Accepted Answer

A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 1 and 2 tied, then 3, then4 
D) 1, then 2 and 3 tied, then 4 
E) 3, 2, 1, 4 
A) 1, 2, 3, 4 
B) 4, 3, 2, 1 
C) 1 and 2 tied, then 3, then4 
D) 1, then 2 and 3 tied, then 4 
E) 3, 2, 1, 4

Question 6

What is the temperature of a burner on an electric stove when its glow is barely visible, at a wavelength of 700 nm? Assume the burner radiates as an ideal blackbody and that 700 nm represents the peak of its emission spectrum.

Accepted Answer

A) 41 K 
B) 240 K 
C) 410 K 
D) 2400 K 
E) 4100 K 
A) 41 K 
B) 240 K 
C) 410 K 
D) 2400 K 
E) 4100 K

Question 7

In a photoelectric effect experiment the stopping potential is:

Accepted Answer

A) the energy required to remove an electron from the sample 
B) the kinetic energy of the most energetic electron ejected 
C) the potential energy of the most energetic electron ejected 
D) the photon energy 
E) the electric potential that causes the electron current to vanish 
A) the energy required to remove an electron from the sample 
B) the kinetic energy of the most energetic electron ejected 
C) the potential energy of the most energetic electron ejected 
D) the photon energy 
E) the electric potential that causes the electron current to vanish

Question 8

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 9

Electromagnetic radiation with a wavelength of 5.7 * 10-12 m is incident on stationary electrons.Radiation that has a wavelength of 6.6 * 10-12 m is detected at a scattering angle of:

Accepted Answer

A) 10 $\degree$ 
B) 40 $\degree$ 
C) 50 $\degree$ 
D) 69 $\degree$ 
E) 111 $\degree$ 
A) 10 $\degree$ 
B) 40 $\degree$ 
C) 50 $\degree$ 
D) 69 $\degree$ 
E) 111 $\degree$

Question 10

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 11

In Compton scattering from stationary electrons the largest change in wavelength occurs when the photon is scattered through:

Accepted Answer

A) 0 $\degree$ 
B) 22.5 $\degree$ 
C) 45 $\degree$ 
D) 90 $\degree$ 
E) 180 $\degree$ 
A) 0 $\degree$ 
B) 22.5 $\degree$ 
C) 45 $\degree$ 
D) 90 $\degree$ 
E) 180 $\degree$

Question 12

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 13

The main problem physicists had with understanding the photoelectric effect before Einstein explained it in terms of photons was:

Accepted Answer

A) the intensity of emitted electrons did not depend on the intensity of the source. 
B) the maximum energy of the emitted electrons did not depend on the frequency of the source. 
C) the maximum energy of the emitted electrons did not depend on the intensity of the source. 
D) the cutoff frequency depended on the material used as a target. 
E) the cutoff frequency did not depend on the material used as a target. 
A) the intensity of emitted electrons did not depend on the intensity of the source. 
B) the maximum energy of the emitted electrons did not depend on the frequency of the source. 
C) the maximum energy of the emitted electrons did not depend on the intensity of the source. 
D) the cutoff frequency depended on the material used as a target. 
E) the cutoff frequency did not depend on the material used as a target.

Question 14

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

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

A free electron and a free proton have the same speed.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 a smaller frequency 
D) the same wavelength and a greater frequency 
E) a longer 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 a smaller frequency 
D) the same wavelength and a greater frequency 
E) a longer wavelength and a smaller frequency

Question 17

The stopping potential for electrons ejected by 6.8 *1014-Hz electromagnetic radiation incident on a certain sample is 1.8 V.The kinetic energy of the most energetic electrons ejected and the work function of the sample, respectively, are:

Accepted Answer

A) 1.8 eV, 2.8 eV 
B) 1.8 eV, 1.0 eV 
C) 1.8 eV, 4.6 eV 
D) 2.8 eV, 1.0 eV 
E) 1.0 eV, 4.6 eV 
A) 1.8 eV, 2.8 eV 
B) 1.8 eV, 1.0 eV 
C) 1.8 eV, 4.6 eV 
D) 2.8 eV, 1.0 eV 
E) 1.0 eV, 4.6 eV

Exam 38: Photons and Matter Waves

Monoenergetic electrons are incident on a single slit barrier.If the energy of each incident electron is increased the central maximum of the diffraction pattern:

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L.If the reflection coefficient R = 0.05,

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 in motion along the x axis has a localized wave function.If it enters a region of space where its potential energy increases,

Identical particles, each with energy E, are incident on the following four potential energy barriers: Rank the barriers in terms of the probability that the particles tunnel through them, from least probability to greatest probability.

What is the temperature of a burner on an electric stove when its glow is barely visible, at a wavelength of 700 nm? Assume the burner radiates as an ideal blackbody and that 700 nm represents the peak of its emission spectrum.

In a photoelectric effect experiment the stopping potential is:

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

Electromagnetic radiation with a wavelength of 5.7 * 10-12 m is incident on stationary electrons.Radiation that has a wavelength of 6.6 * 10-12 m is detected at a scattering angle 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:

In Compton scattering from stationary electrons the largest change in wavelength occurs when the photon is scattered through:

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

The main problem physicists had with understanding the photoelectric effect before Einstein explained it in terms of photons was:

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

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

A free electron and a free proton have the same speed.This means that, compared to the matter wave associated with the proton, the matter wave associated with the electron has:

The stopping potential for electrons ejected by 6.8 *1014-Hz electromagnetic radiation incident on a certain sample is 1.8 V.The kinetic energy of the most energetic electrons ejected and the work function of the sample, respectively, are:

Measurement

Motion Along a Straight Line

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

Fluids

Oscillations

Waves I

Waves II

Temperature, Heat, and the First Law of Thermodynamics

The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Electric Charge

Electric Fields

Gauss Law

Electric Potential

Capacitance

Current and Resistance

Circuits

Magnetic Fields

Magnetic Fields Due to Currents

Induction and Inductance

Electromagnetic Oscillations and Alternating Current

Maxwells Equations; Magnetism of Matter

Electromagnetic Waves

Images

Interference

Diffraction

Relativity

More About Matter Waves

All About Atoms

Conduction of Electricity in Solids

Nuclear Physics

Energy From the Nucleus

Quarks, Leptons, and the Big Bang

Filters

An electron with energy E is incident upon a potential energy barrier of height E_pot < E and thickness L.If the reflection coefficient R = 0.05,

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:

Electromagnetic radiation with a wavelength of 5.7 * 10^-12 m is incident on stationary electrons.Radiation that has a wavelength of 6.6 * 10^-12 m is detected at a scattering angle of:

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

The stopping potential for electrons ejected by 6.8 *10¹⁴-Hz electromagnetic radiation incident on a certain sample is 1.8 V.The kinetic energy of the most energetic electrons ejected and the work function of the sample, respectively, are: