Deck 27: Quantum Physics Blackbody Radiation and Plancks Hypothesis

Question 1

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

Answer 1

decreases

Question 2

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

Answer 2

480 nm

Question 3

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

Answer 3

0.7 eV

Question 4

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 5

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 6

If a blackbody is at 2650° C,what will be the peak wavelength emitted? Wien's displacement constant
)

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

Question 7

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 8

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 9

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 10

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 11

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 12

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

Question 13

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 14

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 15

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

Question 16

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 17

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 18

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 19

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 20

What is the surface temperature of a distant star (which emits light as if it were a blackbody)where the peak wavelength is 474 nm? (Hint: The surface of the human body at 35^° C has a peak wavelength of 9.41 μm).(1 nm = 10−⁹ m = 10^-3 μm)

A) 14,500 K
B) 15,500 K
C) 6120 K
D) 12,200 K
E) ​2040 K

Question 21

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 22

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 23

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 24

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 25

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 26

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 27

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 28

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 29

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 30

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 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 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 33

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 34

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 35

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 36

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 37

Of the following photons,which has the highest energy?

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

Question 38

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 39

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 40

Who was the first to successfully explain the photoelectric effect?

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

Question 41

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 42

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 43

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 44

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 45

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 46

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 47

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 48

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 49

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

Question 50

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 51

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 52

What is the highest frequency of the photons produced by a 28-kV x-ray machine? (h = 6.63 × 10−³⁴ J⋅s)

A) 4.2E+18 Hz
B) 6.8E+15 Hz
C) 4.2E+15 Hz
D) 6.8E+18 Hz
E) ​3.0E+20 Hz

Question 53

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 54

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 55

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 56

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 57

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 58

The spacing between atoms in KCl crystal is 3.1 × 10−¹⁰ m.At what angle from the surface will a beam of 3.57 × 10−¹¹-m x-rays be constructively scattered?

A) 30°
B) 3.3°
C) 0.18°
D) 33°
E) ​103°

Question 59

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 60

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 61

According to Heisenberg,as the uncertainty in the measurement of a particle's momentum is reduced by a factor of 2,by what factor is the uncertainty in that same particle's position changed?

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

Question 62

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 63

If the measured momentum of an electron is 3.6 × 10−²⁷ kg⋅m/s with an uncertainty of 2.6 × 10−²⁹ kg⋅m/s,what is the minimum uncertainty in the position? (h = 6.63 × 10−³⁴ J⋅s)

A) 1.5E-8 m
B) 2.0E-6 m
C) 2.6E-5 m
D) 2.9E-6 m
E) ​7.2E-3 m

Question 64

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

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

Question 65

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 66

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 67

A proton and an electron each have the same de Broglie wavelength.(i)Which has the greater speed,and (ii)which has the greater kinetic energy?

A) (i)the electron,(ii)Either one can have the greater kinetic energy.
B) (i)the proton,(ii)Either one can have the greater kinetic energy.
C) (i)the electron,(ii)the electron
D) (i)the proton,(ii)the proton

Question 68

If an electron has a measured wavelength of 0.832 × 10−¹⁰ m,what is its kinetic energy?
(h = 6.63 × 10−³⁴ J⋅s,1 eV = 1.6 × 10−¹⁹ J,and m_e = 9.11 × 10−³¹ kg)

A) 7640 eV
B) 418 eV
C) 334 eV
D) 218 eV
E) ​70 eV

Question 69

The Heisenberg uncertainty principle places restriction on the precision of simultaneously measuring both position and momentum.This principle can also be applied to the simultaneous measurement of two other variables,which are:

A) force and color.
B) energy and time interval.
C) mass and charge.
D) torque and frequency.

Question 70

Starting from rest,an electron accelerates through a potential difference of 51.6 V.What is its de Broglie wavelength? (h = 6.63 × 10−³⁴ J⋅s,m_e = 9.11 × 10−³¹ kg,and 1 eV = 1.60 × 10−¹⁹ J)

A) 4.4E+13 m
B) 2.4E-10 m
C) 1.7E-10 m
D) 1.1E-24 m
E) ​2.6E-11 m

Question 71

What is the energy of a photon that has the same wavelength as a 11.4-eV electron? (h = 6.63 × 10−³⁴ J⋅s,m_e = 9.11 × 10^-31 kg,1 eV = 1.6 × 10^-19 J)

A) 1140 eV
B) 32 eV
C) 103 eV
D) 3420 eV
E) ​1030 eV

Question 72

The "seeing" ability or resolution of radiation is determined by its wavelength.If the size of an atom is approximately 1.3 × 10−¹⁰ m,how fast must an electron travel to have a wavelength smaller than that of an atom? (m_e = 9.11 × 10−³¹ kg and h = 6.63 × 10−³⁴ J⋅s)

A) 5.6E+6 m/s
B) 5.1E+7 m/s
C) 8.4E+5 m/s
D) 9.5E+6 m/s
E) ​2.4E+3 m/s

Question 73

A proton (mass = 1.67 × 10−²⁷ kg)has a kinetic energy of 2.4 MeV.If its momentum is measured with an uncertainty of 1.18%,what is the minimum uncertainty in its position? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.6 × 10−¹⁹ J)

A) 2.95E-10 m
B) 1.47E-13 m
C) 3.73E-15 m
D) 6.58E-7 m
E) ​2.62E-12 m

Question 74

If a ¹H nucleus,a ²H nucleus,and a ³H nucleus all had the same momentum,which one has the greatest de Broglie wavelength?

A) ¹H
B) ²H
C) ³H
D) All three have the same de Broglie wavelength.

Question 75

The uncertainty principle was derived by whom?

A) Schrödinger
B) Heisenberg
C) de Broglie
D) Compton

Question 76

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 77

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 78

An electron microscope operates with electrons of kinetic energy 58 keV.What is the wavelength of these electrons? Assume this speed is not relativistic.(h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,1 eV = 1.60 × 10−¹⁹ J,and m_e = 9.11 × 10−³¹ kg)

A) 3.57E-20 m
B) 7.69E-13 m
C) 5.10E-12 m
D) 2.28E-10 m
E) ​1.03E-11 m

Question 79

The wave function as derived in Schrödinger's equation is best described as being a measure of which of the following?

A) photon beam frequency
B) photon wavelength
C) particle wavelength
D) probability