Question 1

The quantization of energy, E = nhf, is not important for an ordinary pendulum because:

Accepted Answer

A) the formula applies only to mass-spring oscillators 
B) the allowed energy levels are too closely spaced 
C) the allowed energy levels are too widely spaced 
D) the formula applies only to atoms 
E) the value of h for a pendulum is too large 
A) the formula applies only to mass-spring oscillators 
B) the allowed energy levels are too closely spaced 
C) the allowed energy levels are too widely spaced 
D) the formula applies only to atoms 
E) the value of h for a pendulum is too large B

Question 2

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7*1013 m - 3.The intensity of the beam is:

Accepted Answer

A) 6.8 *10 - 6 W/m2 
B) 3.2 * 102 W/m2  
C) 1.0 *103 W/m2 
D) 2.0 * 103 W/m2 
E) 4.0 * 103 W/m2 
A) 6.8 *10 - 6 W/m2 
B) 3.2 * 102 W/m2  
C) 1.0 *103 W/m2 
D) 2.0 * 103 W/m2 
E) 4.0 * 103 W/m2 D

Question 3

The frequency of light beam A is twice that of light beam B.The ratio EA/EB of photon energies is:

Accepted Answer

A) 1/2 
B) 1/4 
C) 1 
D) 2 
E) 4 
A) 1/2 
B) 1/4 
C) 1 
D) 2 
E) 4 D

Question 4

Light beams A and B have the same intensity but the wavelength associated with beam A is longer than that associated with beam B.The photon flux (number crossing a unit area per unit time)is:

Accepted Answer

A) greater for A than for B 
B) greater for B than for A 
C) the same for A and B 
D) greater for A than for B only if both have short wavelengths 
E) greater for B than for A only if both have short wavelengths 
A) greater for A than for B 
B) greater for B than for A 
C) the same for A and B 
D) greater for A than for B only if both have short wavelengths 
E) greater for B than for A only if both have short wavelengths

Question 5

The main problem that physicists had in understanding blackbody radiation before Planck's work was:

Accepted Answer

A) Blackbody radiation came from objects that were not actually black. 
B) The classically predicted frequency spectrum showed an infinitely large peak at low frequencies. 
C) The classically predicted frequency spectrum showed an infinitely large peak at high frequencies. 
D) The classically predicted frequency spectrum had a minimum intensity rather than a maximum as observed. 
E) The classically predicted frequency spectrum had a maximum intensity that decreased with temperature, rather than increasing as observed. 
A) Blackbody radiation came from objects that were not actually black. 
B) The classically predicted frequency spectrum showed an infinitely large peak at low frequencies. 
C) The classically predicted frequency spectrum showed an infinitely large peak at high frequencies. 
D) The classically predicted frequency spectrum had a minimum intensity rather than a maximum as observed. 
E) The classically predicted frequency spectrum had a maximum intensity that decreased with temperature, rather than increasing as observed.

Question 6

Consider the following: I.A photoelectric process in which all emitted electrons have energy less than hf, where f is the frequency of the incident light.
II.A photoelectric process in which some emitted electrons have kinetic energy greater than hf.
III.Compton scattering from stationary electrons for which the emitted light has a frequency that is greater than that of the incident light.
IV.Compton scattering from stationary electrons for which the emitted light has a frequency that is less than that of the incident light.
The only possible processes are:

Accepted Answer

A) I 
B) III 
C) I and III 
D) I and IV 
E) II and IV 
A) I 
B) III 
C) I and III 
D) I and IV 
E) II and IV

Question 7

The surface of the Sun is at a temperature of approximately 5800 K, and radiates a peak wavelength of 500 nm.According to the Planck radiation law, what is its emitted intensity per unit wavelength at the peak?

Accepted Answer

A) 8.4 W/cm2∙nm 
B) 42 W/cm2∙nm 
C) 84 W/cm2∙nm 
D) 8.4 x 103 W/cm2∙nm 
E) 4.2 x 107 W/cm2∙nm 
A) 8.4 W/cm2∙nm 
B) 42 W/cm2∙nm 
C) 84 W/cm2∙nm 
D) 8.4 x 103 W/cm2∙nm 
E) 4.2 x 107 W/cm2∙nm

Question 8

In Compton scattering from stationary electrons the largest change in wavelength that can occur is:

Accepted Answer

A) 2.43 * 10-15 m 
B) 2.43 *10-12 m 
C) 2.43 * 10-9 m 
D) dependent on the frequency of the incident light 
E) dependent on the work function 
A) 2.43 * 10-15 m 
B) 2.43 *10-12 m 
C) 2.43 * 10-9 m 
D) dependent on the frequency of the incident light 
E) dependent on the work function

Question 9

Consider the following three particles:   Rank them according to the wavelengths of their waves, least to greatest.

Accepted Answer

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

Question 10

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L.The reflection coefficient R:

Accepted Answer

A) is always equal to zero 
B) is always equal to 1 
C) does not depend on E - Epot 
D) is, in general, not equal to zero 
E) is equal to T + 1 where T is the transmission coefficient 
A) is always equal to zero 
B) is always equal to 1 
C) does not depend on E - Epot 
D) is, in general, not equal to zero 
E) is equal to T + 1 where T is the transmission coefficient

Question 11

A free electron in motion along the x axis has a localized wave function.The uncertainty in its momentum is decreased if:

Accepted Answer

A) the wave function is made more narrow 
B) the wave function is made less narrow 
C) the wave function remains the same but the energy of the electron is increased 
D) the wave function remains the same but the energy of the electron is decreased 
E) none of the above 
A) the wave function is made more narrow 
B) the wave function is made less narrow 
C) the wave function remains the same but the energy of the electron is increased 
D) the wave function remains the same but the energy of the electron is decreased 
E) none of the above

Question 12

The significance of $\vert$$\Psi$$\vert$2 is:

Accepted Answer

A) probability 
B) energy 
C) probability density 
D) energy density 
E) wavelength 
A) probability 
B) energy 
C) probability density 
D) energy density 
E) wavelength

Question 13

An electron with energy E is incident upon a potential energy barrier of height Epot > E and thickness L.The transmission coefficient T:

Accepted Answer

A) is zero 
B) decreases exponentially with L 
C) is proportional to 1/L 
D) is proportional to 1/L2 
E) is non-zero and independent of L 
A) is zero 
B) decreases exponentially with L 
C) is proportional to 1/L 
D) is proportional to 1/L2 
E) is non-zero and independent of L

Question 14

Rank following electromagnetic radiations according to the energies of their photons, from least to greatest.

Accepted Answer

A) 1, 2, 3, 4 
B) 4, 2, 1, 3 
C) 4, 1, 2, 3 
D) 3, 2, 1, 4 
E) 3, 1, 2, 4 
A) 1, 2, 3, 4 
B) 4, 2, 1, 3 
C) 4, 1, 2, 3 
D) 3, 2, 1, 4 
E) 3, 1, 2, 4

Question 15

In Compton scattering from stationary particles the maximum change in wavelength can be made smaller by using:

Accepted Answer

A) higher frequency radiation 
B) lower frequency radiation 
C) more massive particles 
D) less massive particles 
E) particles with greater charge 
A) higher frequency radiation 
B) lower frequency radiation 
C) more massive particles 
D) less massive particles 
E) particles with greater charge

Question 16

A non-relativistic free electron has kinetic energy K.If its wavelength doubles, its kinetic energy is:

Accepted Answer

A) 4 K 
B) 2 K 
C) K 
D) K/2 
E) K/4 
A) 4 K 
B) 2 K 
C) K 
D) K/2 
E) K/4

Question 17

The work function for a certain sample is 2.3 eV.The stopping potential for electrons ejected from the sample by 7.0 * 1014-Hz electromagnetic radiation is:

Accepted Answer

A) 0 V 
B) 0.60 V 
C) 2.3 V 
D) 2.9 V 
E) 5.2 V 
A) 0 V 
B) 0.60 V 
C) 2.3 V 
D) 2.9 V 
E) 5.2 V

Question 18

A free electron has a momentum of 5.0 *10-24 kg .m/s.Its wavelength, as given by its wave function, is:

Accepted Answer

A) 1.3 * 10-8 m 
B) 1.3 * 10-10 m 
C) 2.3 * 10-11 m 
D) 2.3 * 10-13 m 
E) none of these 
A) 1.3 * 10-8 m 
B) 1.3 * 10-10 m 
C) 2.3 * 10-11 m 
D) 2.3 * 10-13 m 
E) none of these

Question 19

Maxwell's equations are to electric and magnetic fields as __________ equation is to the wave function of the particle.

Accepted Answer

A) Einstein's 
B) Fermi's 
C) Newton's 
D) Schrödinger's 
E) Bohr's 
A) Einstein's 
B) Fermi's 
C) Newton's 
D) Schrödinger's 
E) Bohr's

Question 20

In order to tunnel through a potential barrier a particle must:

Accepted Answer

A) have energy greater than the barrier height 
B) have spin 
C) be massive 
D) have a wavelength longer than the barrier width 
E) none of the above 
A) have energy greater than the barrier height 
B) have spin 
C) be massive 
D) have a wavelength longer than the barrier width 
E) none of the above

Exam 38: Photons and Matter Waves

The quantization of energy, E = nhf, is not important for an ordinary pendulum because:

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7*1013 m - 3.The intensity of the beam is:

The frequency of light beam A is twice that of light beam B.The ratio EA/EB of photon energies is:

Light beams A and B have the same intensity but the wavelength associated with beam A is longer than that associated with beam B.The photon flux (number crossing a unit area per unit time)is:

The main problem that physicists had in understanding blackbody radiation before Planck's work was:

The surface of the Sun is at a temperature of approximately 5800 K, and radiates a peak wavelength of 500 nm.According to the Planck radiation law, what is its emitted intensity per unit wavelength at the peak?

In Compton scattering from stationary electrons the largest change in wavelength that can occur is:

Consider the following three particles: Rank them according to the wavelengths of their waves, least to greatest.

An electron with energy E is incident upon a potential energy barrier of height Epot < E and thickness L.The reflection coefficient R:

A free electron in motion along the x axis has a localized wave function.The uncertainty in its momentum is decreased if:

The significance of ∣\vert∣Ψ\PsiΨ∣\vert∣ 2 is:

An electron with energy E is incident upon a potential energy barrier of height Epot > E and thickness L.The transmission coefficient T:

Rank following electromagnetic radiations according to the energies of their photons, from least to greatest.

In Compton scattering from stationary particles the maximum change in wavelength can be made smaller by using:

A non-relativistic free electron has kinetic energy K.If its wavelength doubles, its kinetic energy is:

The work function for a certain sample is 2.3 eV.The stopping potential for electrons ejected from the sample by 7.0 * 1014-Hz electromagnetic radiation is:

A free electron has a momentum of 5.0 *10-24 kg .m/s.Its wavelength, as given by its wave function, is:

Maxwell's equations are to electric and magnetic fields as __________ equation is to the wave function of the particle.

In order to tunnel through a potential barrier a particle must:

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

The concentration of photons in a uniform light beam with a wavelength of 500 nm is 1.7*10¹³ m ^- ³.The intensity of the beam is:

The frequency of light beam A is twice that of light beam B.The ratio E_A/E_B of photon energies is:

An electron with energy E is incident upon a potential energy barrier of height E_pot < E and thickness L.The reflection coefficient R:

The significance of $\vert$ $\Psi$ $\vert$ ² is:

An electron with energy E is incident upon a potential energy barrier of height E_pot > E and thickness L.The transmission coefficient T:

The work function for a certain sample is 2.3 eV.The stopping potential for electrons ejected from the sample by 7.0 * 10¹⁴-Hz electromagnetic radiation is:

A free electron has a momentum of 5.0 *10^-24kg .m/s.Its wavelength, as given by its wave function, is: