Deck 27: Quantum Physics

Question 1

According to Einstein,what is true of the stopping potential for a photoelectric current as the wavelength of incident light becomes shorter?

A)increases
B)decreases
C)remains constant
D)stopping potential is directly proportional to wavelength

Answer 1

increases

Question 2

If a blackbody is at 2650° C,what will be the peak wavelength emitted? Wien's displacement constant b = 2.898 × 10^-3 m·K.

A)1.09 μm
B)0.34 μm
C)0.99 μm
D)9.9 μm
E)​0.11 μm

Answer 2

0.99 μm

Question 3

Planck's quantum theory is compatible with the experimental data related to which of the following?

A)blackbody radiation
B)the photoelectric effect
C)line spectra emitted by hydrogen gas
D)all of the above

Answer 3

all of the above

Question 4

Classical theories predict that most of the energy from a blackbody should be radiated:

A)as thermal radiation in the infrared region.
B)at the wavelength given by Wien's displacement law.
C)as ultraviolet light.
D)a blackbody should not radiate.

Question 5

Which of the following devices represent(s)a practical application of the photoelectric effect?

A)hologram
B)photocell
C)both of the above choices
D)none of the above choices

Question 6

According to Einstein,as the wavelength of the incident monochromatic light beam becomes shorter,the work function of a target material in a phototube:

A)increases.
B)decreases.
C)remains constant.
D)is directly proportional to wavelength.

Question 7

If a monochromatic light beam with quantum energy value of 1.6 eV incident upon a photocell where the work function of the target metal is 0.9 eV,what is the maximum kinetic energy of ejected electrons?

A)2.5 eV
B)1.8 eV
C)0.7 eV
D)3.2 eV
E)​1.3 eV

Question 8

A quantum of radiation has an energy of 1.5 keV.What is its frequency? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.60 × 10−¹⁹ J)

A)3.6E+14 Hz
B)3.6E+17 Hz
C)2.3E+17 Hz
D)2.4E+18 Hz
E)​1.4E+17 Hz

Question 9

Star A has the peak of its blackbody radiation at λ_A.Star B has its peak at λ_B,which is one-third that of λ_A.If Star A's surface temperature is T_A,how does the surface temperature T_B of Star B compare?

A)T_B = T_A/9
B)T_B = 3T_A
C)T_B = 9 T_A
D)T_B = T_A/3

Question 10

The ultraviolet catastrophe predicts that:

A)all objects should radiate extreme amounts of ultraviolet light.
B)as an object gets hotter its light will change from dull red to blue white.
C)a black body can absorb an infinite amount of radiation if the radiation is in the ultraviolet region.
D)the radiated energy approaches zero as the wavelength approaches zero.

Question 11

A monochromatic light beam is incident on a barium target,which has a work function of 2.6 eV.If a stopping potential of 1.2 V is required,what is the light beam photon energy?

A)2.6 eV
B)1.4 eV
C)1.2 eV
D)3.8 eV
E)​0.7

Question 12

Blue light will not eject electrons from a certain metal;however,which one of the following may possibly eject electrons from that metal?

A)infrared
B)ultraviolet
C)red
D)green

Question 13

According to Wien's displacement law,if the absolute temperature of a radiating blackbody is tripled,then the peak wavelength emitted will change by what factor?

A)1/3
B)1
C)3
D)9

Question 14

As the temperature of a radiation emitting blackbody becomes lower,what happens to the peak wavelength of the radiation?

A)remains constant
B)increases
C)decreases
D)is directly proportional to temperature

Question 15

Which of the following statements best describes the relation between the quantum theory and the photoelectric effect experiment?

A)Quantum theory explains the photoelectric effect.
B)The photoelectric effect contradicts quantum theory.
C)Quantum theory has no bearing on the photoelectric effect.
D)The photoelectric effect explains quantum theory.

Question 16

If a quantum of radiation has an energy of 2.10 keV,what is its wavelength? (h = 6.63 × 10−³⁴ J⋅s,1 eV = 1.60 × 10−¹⁹ J,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)0.95 nm
B)197 nm
C)0.59 nm
D)1.24 nm
E)​0.14 nm

Question 17

As the temperature of a radiation emitting blackbody becomes higher,what happens to the peak wavelength of the radiation?

A)increases
B)decreases
C)remains constant
D)is directly proportional to temperature

Question 18

According to Einstein,increasing the brightness of a beam of light without changing its color will increase:

A)the number of photons.
B)the energy of each photon.
C)the speed of the photons.
D)the frequency of the photons.

Question 19

What is the surface temperature of a distant star (which emits light as if it were a blackbody)where the peak wavelength is 422 nm? (Hint: The surface of the human body at 35ºC has a peak wavelength of 9.41 μm).(1 nm = 10−⁹ m = 10^-3 μm)

A)12,900 K
B)13,800 K
C)6870 K
D)13,700 K
E)​2290 K

Question 20

Of the following photons,which has the highest energy?

A)infrared
B)microwave
C)visible
D)ultraviolet

Question 21

Of the following photons,which has the lowest energy?

A)visible
B)ultraviolet
C)infrared
D)microwave

Question 22

What is the energy of a photon whose frequency is 2.9 × 10²⁰ Hz? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.60 × 10−¹⁹ J)

A)0.2 MeV
B)1.2 MeV
C)1.9 MeV
D)3.1 MeV
E)​0.8 MeV

Question 23

Which change will not change the kinetic energy of the most energetic electrons emitted in the photoelectric effect?

A)changing the brightness of the light
B)changing the frequency of the light
C)changing the metal the light is hitting
D)All of the above will change the electron's kinetic energy.

Question 24

How much energy (in eV)does a photon of orange light (λ = 609 nm)have? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)3.27 eV
B)0.31 eV
C)2.04 eV
D)0.68 eV
E)​5.23 eV

Question 25

Of the following energies for photons,which is the least energy that could result in photoelectron production if the work function is 3.77 eV?

A)2.72 eV
B)3.19 eV
C)4.57 eV
D)6.98 eV
E)​6.53 eV

Question 26

What is the wavelength of a monochromatic light beam,where the photon energy is 4.14 × 10−¹⁹ J? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)160 nm
B)480 nm
C)72 nm
D)187 nm
E)​915 nm

Question 27

Violet light (λ = 430 nm)is incident on a piece of potassium (φ = 2.20 eV).What is the maximum kinetic energy of the ejected photoelectrons? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)2.43 eV
B)0.69 eV
C)2.89 eV
D)5.09 eV
E)​0.96 eV

Question 28

Light of wavelength 439 nm is incident on a metallic surface with a resultant photoelectric stopping potential of 1.2 V.What is the work function of the metal? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)1.63 eV
B)2.83 eV
C)4.03 eV
D)0.82 eV
E)​2.02 eV

Question 29

Who was the first to successfully explain the photoelectric effect?

A)Planck
B)Young
C)Bohr
D)Einstein

Question 30

A sodium vapor lamp has a power output of 60 W.If 547 nm is the average wavelength of the source,about how many photons are emitted per second? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)10¹⁸
B)10²⁰
C)10³⁹
D)10²⁹
E)​10²⁸

Question 31

A helium-neon laser emits red light having a wavelength of 632.8 nm and a power of 1.85 mW.How many photons are emitted each second? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)5.9E+15
B)3.7E+34
C)5.9E+24
D)5.9E+18
E)​1.2E+17

Question 32

What is the wavelength of a monochromatic light beam,where the photon energy is 2.15 eV? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 nm = 10−⁹ m,and 1 eV = 1.6 × 10−¹⁹ J)

A)308 nm
B)578 nm
C)223 nm
D)156 nm
E)​475 nm

Question 33

A photon absorbed by an electron will give up more energy to the electron if the photon:

A)is not spread out over many electrons.
B)is moving faster.
C)is moving slower.
D)has a higher frequency.

Question 34

Of photons of red,yellow,light,and blue light,which photons have the greatest energy?

A)red
B)yellow
C)green
D)blue

Question 35

Sources of red,blue,and yellow light each emit light with a power of 50 mW.Which source emits more photons per second?

A)the red source
B)the blue source
C)the yellow source
D)They all emit the same number per second.

Question 36

What is the frequency of monochromatic light where the photon energy is 4.3 × 10−¹⁹ J? (h = 6.63 × 10−³⁴ J⋅s)

A)4.3E+15 Hz
B)2.1E+15 Hz
C)6.5E+14 Hz
D)1.9E+14 Hz
E)​6.5E+13 Hz

Question 37

A light beam is shining on a metal target that has a work function of 1.8 eV.If a stopping potential of 0.7 V is required,what is the wavelength of the incoming monochromatic light? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)497 nm
B)166 nm
C)796 nm
D)1130 nm
E)​691 nm

Question 38

An ultraviolet light beam having a wavelength of 217 nm is incident on a molybdenum surface with work function of 4.9 eV.What is the stopping potential? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.6 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)10.6 V
B)5.3 V
C)0.8 V
D)0.4 V
E)​5.7 V

Question 39

Light of wavelength 6.9 × 10−⁷ m has an energy of: (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s)

A)2.9E-19 J
B)9.6E-20 J
C)3.1E-19 J
D)4.3E-20 J
E)​3.2E-20 J

Question 40

Of photons of red,yellow,green,and blue light,which photons have the least energy?

A)red
B)blue
C)green
D)yellow

Question 41

Who conceived the idea of using a crystal for observing diffraction of x-rays?

A)Roentgen
B)von Laue
C)W.L.Bragg
D)W.H.Bragg

Question 42

A light-emitting diode has a power output of 0.3 W.If 590 nm is the average wavelength of the source,about how many photons are emitted per second? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)10²¹
B)10²⁵
C)10¹⁸
D)10²⁹

Question 43

If an x-ray machine were designed to operate at two separate accelerating voltages,one double the other,how would the shortest wavelength,λ_min,hν,and the maximum frequency,f_max,hν,at the higher voltage compare to those (λ_min,lv,f_max,lv)at the lower voltage?
Λ_min,hv/ λ_min,lv = ________,f_max,hv/ f_max,lv =________:

A)2,2.
B)2,1/2.
C)1/2,2.
D)1/2,1/2.

Question 44

If barium has a work function of 2.6 eV,what is its cutoff wavelength when used as a phototube target? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J and 1 nm = 10−⁹ m)

A)765 nm
B)478 nm
C)777 nm
D)380 nm

Question 45

What is the maximum velocity of a photoelectron emitted from a surface with work function 3.5 eV when illuminated by 289 nm ultraviolet light? (m_electron = 9.11 × 10−³¹ kg,h = 6.63 × 10−³⁴ J⋅s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)3.75E+5 m/s
B)5.31E+5 m/s
C)7.28E+2 m/s
D)8.62E+5 m/s
E)​1.60E+6 m/s

Question 46

What is the minimum x-ray wavelength produced when electrons are accelerated through a potential of 46,800 V? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 eV = 1.60 × 10−¹⁹ J)

A)4.25E-11 m
B)8.85E-12 m
C)4.01E-12 m
D)2.66E-11 m
E)​6.80E-11 m

Question 47

What is the highest frequency of the photons produced by a 29-kV x-ray machine? (h = 6.63 × 10−³⁴ J⋅s)

A)4.4E+18 Hz
B)7.0E+15 Hz
C)4.4E+15 Hz
D)7.0E+18 Hz
E)​3.1E+20 Hz

Question 48

In an x-ray diffraction experiment,using x-rays of wavelength λ = 0.434 × 10−¹⁰ m,a first-order maximum occurred at 8° off the crystal plane.Find the distance d between crystal planes.

A)1.56E-10 m
B)2.19E-11 m
C)4.88E-10 m
D)1.70E-9 m
E)​3.12E-10 m

Question 49

The microwave in the kitchen has a label that indicates it produces its microwaves at a frequency of 2450 MHz.What is the energy associated with one of these microwave photons? (h = 6.63 × 10−³⁴ J⋅s)

A)3.19 × 10^-2 eV
B)2.45 eV
C)1.02 × 10^-5 eV
D)1.62 eV

Question 50

Bragg reflection results in a first-order maximum at 12.2°.In this case,at what angle would the second-order maximum occur?

A)24.4°
B)12.2°
C)7.79°
D)25.0°
E)​78.5°

Question 51

Light of wavelength 521 nm is incident on a target metal that has a work function of 1.6 eV.What stopping potential is required for this combination in a phototube? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and 1 nm = 10−⁹ m)

A)4.0 V
B)0.8 V
C)2.0 V
D)0.4 V
E)​2.4 V

Question 52

An important use of x-ray diffraction was:

A)the observation of Compton scattering.
B)determining the structure of the DNA molecule.
C)production of positrons.
D)observation of the photoelectric effect.

Question 53

A detector absorbs 1.0 × 10⁹ photons of monochromatic light and their total energy is found to be 0.33 nJ.What is the wavelength associated with these photons? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s)

A)600 nm
B)540 nm
C)400 nm
D)500 nm

Question 54

X-ray production occurs in which process?

A)photons hitting a metal,emitting electrons
B)electrons hitting a metal,emitting photons
C)photons hitting a metal,emitting x-rays
D)electrons hitting a metal and scattering elastically

Question 55

Rosalind Franklin was

A)the maiden name of the wife of a president.
B)the producer of the x-ray diffraction photographs that led to the DNA structure.
C)the person who discovered that salt forms a crystal.
D)the discoverer of x-rays.

Question 56

What potential difference is needed to accelerate a proton from rest to give it a wavelength of 2.00 × 10^-12 m?

A)411 V
B)206 V
C)1650 V
D)617 V

Question 57

In Bragg's law,2d sin θ = mλ,how is θ measured?

A)from the reflecting crystal plane
B)from the normal to the reflecting crystal plane
C)from the direction of the incident beam
D)from the normal to the direction of the incident beam

Question 58

Changing the accelerating voltage of an x-ray machine without changing the target material must change:

A)the work function of the material.
B)the wavelength of all the x-rays produced.
C)the wavelength of the minimum wavelength x-ray that will be produced.
D)Both b and c are correct.

Question 59

If the minimum x-ray wavelength produced is 17 × 10−¹² m,through what potential are the electrons accelerated in order to generate this radiation? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 eV = 1.60 × 10−¹⁹ J)

A)1.17E+5 V
B)2.44E+4 V
C)1.10E+4 V
D)7.31E+4 V
E)​1.87E+5 V

Question 60

The spacing between atoms in KCl crystal is 3.1 × 10−¹⁰ m.At what angle from the surface will a beam of 2.23 × 10−¹¹-m x-rays be constructively scattered?

A)30°
B)2.1°
C)0.11°
D)20°
E)​64°

Question 61

According to de Broglie,as the momentum of a moving particle is tripled,the corresponding wavelength changes by what factor?

A)1/9
B)1/3
C)3
D)9

Question 62

The Compton wavelength,h/m_ec,equals 0.002 43 nm.In Compton scattering,what is the greatest shift,Δλ,in wavelength that can occur?

A)Δλ > 2 h/m_ec
B)Δλ = 2 h/m_ec
C)Δλ = h/m_ec
D)Δλ < h/m_ec

Question 63

X-rays with an energy of 400 keV undergo Compton scattering from a target. The scattered rays are deflected at an angle of 38° relative to the direction of the incident rays.
​What is the energy of the scattered x-rays?

A)​343 keV
B)​300 keV
C)​400 keV
D)​2410 keV

Question 64

According to the de Broglie hypothesis,which of the following statements is applicable to the wavelength of a moving particle?

A)directly proportional to its energy
B)directly proportional to its momentum
C)inversely proportional to its energy
D)inversely proportional to its momentum

Question 65

That light has a dual nature is referring to light

A)having high- or low-energy photons.
B)acting as waves and particles.
C)having energy and momentum.
D)undergoing pair production.

Question 66

The de Broglie wavelength of a 0.069 kg golf ball is 4.67 × 10−³⁴m.What is its speed? (h = 6.63 × 10−³⁴ J⋅s)

A)10 m/s
B)21 m/s
C)3.1 m/s
D)90 m/s
E)​4.5 m/s

Question 67

In the Compton effect,what is the greatest change in wavelength that can occur? (h = 6.63 × 10^-34 J·s,m_electron = 9.11 × 10^-31 kg,and c = 3.00 × 10⁸ m/s)

A)2.43 × 10^-12 m
B)4.85 × 10^-12 m
C)equal to the incident wavelength
D)infinite

Question 68

A beam of photons of wavelength 0.55 nm undergoes Compton scattering from free electrons.
​What is the momentum of the photons that emerge at a 55° angle with respect to the incident beam?

A)​1.20E-24 kg·m/s
B)​1.20E-33 kg·m/s
C)​3.65E-34 kg·m/s
D)​8.31E+23 kg·m/s

Question 69

Which of the following is an indication that one is dealing with a wave property instead of a particle property?

A)energy
B)quanta
C)interference
D)momentum

Question 70

What is the energy of a photon with the Compton wavelength (0.00437 nm)? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 eV = 1.60 × 10−¹⁹ J)

A)4.55E-14 eV
B)2.84E+5 eV
C)2.84E+1 eV
D)3.52E-6 eV
E)​4.55E+5 eV

Question 71

For which of the following objects,each with the same kinetic energy,is the de Broglie wavelength the largest?​

A)​car
B)​planet
C)​electron
D)​house fly

Question 72

Which process cannot occur if only one photon is involved?

A)Compton effect
B)pair production
C)the photoelectric effect
D)x-ray production

Question 73

​What is the kinetic energy of the recoiling electrons?

A)​56.9 J
B)​51.5 J
C)​34.3 J
D)​13.7 J

Question 74

The Compton experiment demonstrated which of the following when an x-ray photon collides with an electron?

A)Momentum is conserved.
B)Energy is conserved.
C)Momentum and energy are both conserved.
D)Wavelength of scattered photon equals that of incident photon.

Question 75

What is the de Broglie wavelength for a proton (m = 1.67 × 10−²⁷ kg)moving at a speed of 2.9 × 10⁶ m/s? (h = 6.63 × 10−³⁴ J⋅s)

A)6.84E-14 m
B)2.06E-14 m
C)2.29E-13 m
D)1.37E-13 m
E)​3.82E-13 m

Question 76

X-rays of wavelength of 0.0656 nm undergo Compton scattering from free electrons in carbon.What is the wavelength of photons scattered at 82.5° relative to the incident beam? (h = 6.63 × 10−³⁴ J⋅s,m_e = 9.11 × 10−³¹ kg,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A)0.0656 nm
B)0.0677 nm
C)0.0848 nm
D)0.0719 nm
E)​0.0659 nm

Question 77

Due to the dual nature of light and matter,either can act in an experiment as if it is a wave or a particle.In which experiment is the wave aspect exhibited for matter?

A)the Davisson and Germer experiment
B)the photoelectric effect
C)pair production
D)Compton scattering

Question 78

The electron microscope's main advantage over the optical microscope is which of the following?

A)greater ease of portability
B)dispenses with need for a lens
C)higher power lens used
D)higher resolution possible

Question 79

A beam of photons of wavelength 0.55 nm undergoes Compton scattering from free electrons.
​What is the energy of the photons that emerge at a 35° angle with respect to the incident beam?

A)​2.3 keV
B)​10.9 keV
C)​36.0 keV
D)​3.0 keV

Question 80

In regard to the Compton scattering experiment with x-rays incident upon a carbon block,as the scattering angle becomes larger,what happens to the magnitude of difference between the incident and scattered wavelengths?

A)increases
B)decreases
C)remains constant
D)difference is maximum at a 45° angle of scatter