Deck 27: Early Quantum Physics and the Photon

Question 1

A problem with the classical theory for radiation from a blackbody was that the theory predicted too much radiation in the ________________ wavelengths.

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

Answer 1

ultraviolet

Question 2

A 2.00 eV photon has what frequency?

A) 6.40 $\times$ 10¹⁴ Hz
B) 1.86 $\times$ 10¹⁴ Hz
C) 3.15 $\times$ 10¹⁴ Hz
D) 7.21 $\times$ 10¹⁴ Hz
E) 4.83 $\times$ 10¹⁴ Hz

Answer 2

4.83 $\times$ 10¹⁴ Hz

Question 3

A 1.00 mW laser produces photons of wavelength 633 nm.How many photons per second does the laser emit?

A) 6.33 $\times$ 10¹⁰
B) 1.27 $\times$ 10¹²
C) 3.18 $\times$ 10¹⁵
D) 4.28 $\times$ 10¹⁶
E) 1.60 $\times$ 10¹⁹

Answer 3

3.18 $\times$ 10¹⁵

Question 4

Photons of red light cause a surface to emit photoelectrons with maximum kinetic energy K(red).If photons of blue light of the same intensity are now used in the experiment,which of the following statements is true about the photoelectrons emitted (if any are emitted)?

A) no photoelectrons are emitted
B) maximum K(blue) < K(red)
C) maximum K(blue) = K(red)
D) maximum K(blue) > K(red)
E) none of these choices are true

Question 5

Light of wavelength 400 nm bombards a surface with work function 2.46 eV. What is the maximum kinetic energy of the photoelectrons from this surface?

A) no photoelectrons are emitted
B) 2.46 eV
C) 3.30 eV
D) 0.640 eV
E) 0.840 eV

Question 6

The work function of a surface is 6.53 $\times$ 10^-19 J.What is this quantity in eV?

A) 2.46
B) 3.13
C) 3.93
D) 4.08
E) 4.70

Question 7

What is the threshold frequency for a surface with work function 4.14 eV?

A) 1.00 $\times$ 10¹² Hz
B) 1.00 $\times$ 10¹³ Hz
C) 1.00 $\times$ 10¹⁴ Hz
D) 1.00 $\times$ 10¹⁵ Hz
E) 1.00 $\times$ 10¹⁶ Hz

Question 8

Sodium has a work function of 2.46 eV.Of the following wavelengths,which is the one of the longest wavelength that could cause photoelectrons to be released from the sodium?

A) 300 nm
B) 400 nm
C) 500 nm
D) 600 nm
E) 700 nm

Question 9

In the Compton effect,a photon of wavelength $\lambda$ and frequency f is scattered from an electron.Initially,at rest

A) the electron gains energy from the photon so that the scattered photon's wave length is less than $\lambda$ .
B) the electron gives energy to the scattered photon so the photon's frequency is greater than f.
C) momentum is not conserved,but energy is conserved.
D) the photon loses energy so that the scattered photon has a frequency less than f.

Question 10

An x-ray photon of energy 3.20 $\times$ 10^-15 J has what wavelength?

A) 200 nm
B) 62.1 pm
C) 32.7 nm
D) 5.73 pm
E) 1.07 nm

Question 11

Silver has a work function of 4.73 eV. Photons of threshold frequency would be described as which of the following?

A) infrared
B) red
C) yellow
D) blue
E) ultraviolet

Question 12

Photons from a source each have energy 3.30 eV.Photons from a second source have double the frequency of those from the first source.What is the energy of a photon from the second source?

A) 6.60 eV
B) 13.2 eV
C) 1.65 eV
D) 0.825 eV
E) 3.96 eV

Question 13

Using the quantum theory of EM waves,___________ was successful in explaining the photoelectric effect.(He later won a Nobel Prize for this work.)

A) Hertz
B) Planck
C) Einstein
D) Maxwell
E) Bohr

Question 14

A laser beam emits 2.5 $\times$ 10²⁰ photons per second with a wavelength of 663 nm.What is the power output of this laser?

A) 51 mW
B) 67 mW
C) 51 W
D) 75 W
E) 93 W

Question 15

Two lasers emit equal numbers of photons per second.If the first laser emits red light and the second emits blue light,the power radiated by the first is

A) equal to that emitted by the second.
B) greater than that emitted by the second.
C) less than that emitted by the second.
D) dependent on the time interval of the emission.

Question 16

A photon of frequency 6.40 $\times$ 10¹⁴ Hz has what energy?

A) 1.26 eV
B) 1.93 eV
C) 2.11 eV
D) 2.65 eV
E) 3.17 eV

Question 17

The phenomena of quantization is NOT found in the following

A) charge on an electron.
B) photoelectric effect.
C) gravitational effect.
D) Compton effect.

Question 18

The energy of a photon of wavelength 400 nm is _____________.

A) 3.11 $\times$ 10^-19 J
B) 3.50 $\times$ 10^-19 J
C) 3.87 $\times$ 10^-19 J
D) 4.25 $\times$ 10^-19 J
E) 4.97 $\times$ 10^-19 J

Question 19

_______________ theoretical assumptions on quantization overcame the difficulty with a major problem with understanding blackbody radiation.

A) Hertz's
B) Planck's
C) Einstein's
D) Maxwell's
E) Bohr's

Question 20

In a photoelectric effect experiment,the frequency of photons bombarding the surface is increased until photoelectrons just start to leave the surface.If this occurs at a frequency of 6.0 $\times$ 10¹⁴ Hz,what is the work function of the surface?

A) 1.0 eV
B) 1.5 eV
C) 2.0 eV
D) 2.5 eV
E) 3.0 eV

Question 21

X-rays are produced using a potential difference of V.The spectrum of wavelengths is found to contain

A) a single wavelength.
B) all wavelengths from zero up to a maximum.
C) all wavelengths from a minimum to a maximum.
D) only discrete wavelengths.

Question 22

Electrons are accelerated through a potential difference V and then strike a dense target.In the x-rays that are produced

A) the maximum wavelength depends on V.
B) the wavelength of the characteristic peaks depend on V.
C) the minimum wavelength depends on V.
D) the wavelength of the Bremsstrahlung depends on V.

Question 23

Monochromatic light shines on a surface with work function 1.80 eV. The maximum energy of the emitted photoelectrons is 0.620 eV. What is the wavelength of the monochromatic light?

A) 200 nm
B) 290 nm
C) 689 nm
D) 602 nm
E) 512 nm

Question 24

In the Compton effect a photon of wavelength $\lambda$ and frequency f is scattered from and electron,initially at rest.In this process

A) the photon loses energy so that the scattered photon has frequency less than f.
B) the momentum is not conserved,but the energy is.
C) the electron gives energy to the scattered photon so that the photon's frequency is greater than f.
D) the electron gains energy from the photon so that the scattered photon's wavelength is less than f.

Question 25

Electrons are accelerated through a potential difference of 90.0 kV and directed at a tungsten target to produce x-rays.What is the shortest wavelength of the x-rays produced?

A) 669 pm
B) 508 pm
C) 72.6 pm
D) 13.8 pm
E) 14.3 pm

Question 26

A 100 keV photon undergoes Compton scattering.What is the greatest amount of kinetic energy that can be given to the electron in this process?

A) 100 keV
B) 71.8 keV
C) 83.6 keV
D) 28.2 keV
E) 16.4 keV

Question 27

Photons of energy 4.20 eV bombard a surface,which emits photoelectrons with kinetic energies for 0 to 1.80 eV. What is the threshold frequency for this surface?

A) 1.35 $\times$ 10¹⁴ Hz
B) 5.81 $\times$ 10¹⁴ Hz
C) 1.35 $\times$ 10¹⁵ Hz
D) 7.74 $\times$ 10¹⁴ Hz
E) 7.74 $\times$ 10¹⁵ Hz

Question 28

An x-ray tube produces photons down to a 0.0827 nm wavelength.What is the accelerating potential for this tube?

A) 123 kV
B) 9.22 kV
C) 8.00 kV
D) 10.0 kV
E) 15.0 kV

Question 29

In a Compton scattering experiment,the scattered photon has a wavelength of 6.55 pm.If the scattering angle is 50 $^{\circ}$ ,what is the wavelength of the incident photon?

A) 5.68 pm
B) 7.42 pm
C) 3.28 pm
D) 0.868 pm
E) 2.43 pm

Question 30

An x-ray photon with wavelength 15.0 pm is scattered at 84.0 $^{\circ}$ by an electron.What is the resulting kinetic energy of the electron?

A) 568 keV
B) 59.5 keV
C) 30.1 keV
D) 15.0 keV
E) 10.5 keV

Question 31

The spectra,such as Ångström found for low-pressure gas in a discharge tube,are of what type?

A) continuous
B) discrete
C) blackbody
D) band
E) dark-line

Question 32

The Compton shift equation for the wavelength shift is derived from the law(s)of

A) conservation of momentum.
B) conservation of energy.
C) conservation of charge.
D) conservation of momentum and charge.
E) conservation of energy and momentum.

Question 33

In a Compton scattering experiment,the scattered photon has a wavelength of 6.55 pm.If the scattering angle is 50 $^{\circ}$ ,what is the energy of the incident photon?

A) 1.43 MeV
B) 218 keV
C) 380 keV
D) 117 keV
E) 66.3 keV

Question 34

An electron passing close to a target nucleus slows and radiates away some of its energy.What is the process called?

A) blackbody radiation
B) photoelectric effect
C) stimulated emission
D) bremsstrahlung
E) Compton effect

Question 35

The number of electrons per second ejected from a metal in the photoelectric effect

A) is proportional to the threshold frequency of the metal.
B) is proportional to the intensity of the incident light.
C) is proportional to the wavelength of the incident light.
D) is proportional to the frequency of the incident light.

Question 36

In a photoelectric effect experiment,light of a single wavelength is incident on the metal surface.As the intensity of the incident light is increased

A) the stopping potential decreases.
B) the stopping potential increases.
C) the work function decreases.
D) the work function increases.
E) None of these choices are true.

Question 37

The maximum shift in wavelength in Compton scattering is what multiple of the Compton wavelength (h/m_iss)?

A) 0.5
B) 1
C) 2
D) 4
E) unlimited

Question 38

An x-ray photon with wavelength 15.0 pm is scattered at 84.0 $^{\circ}$ by an electron.What is the wavelength of the scattered photon?

A) 31.0 pm
B) 14.9 pm
C) 1.57 pm
D) 17.2 pm
E) 12.8 pm

Question 39

Electrons are accelerated through a potential difference of 90.0 kV and directed at a tungsten target to produce x-rays.What is the cutoff frequency in the x-ray spectrum produced?

A) 2.17 $\times$ 10¹⁹ Hz
B) 2.10 $\times$ 10¹⁹ Hz
C) 1.17 $\times$ 10²¹ Hz
D) 9.25 $\times$ 10²¹ Hz
E) 6.20 $\times$ 10¹⁵ Hz

Question 40

In the formula 1/ $\lambda$ = R (1 / n_f² - 1/n_i²), Balmer found that for the visible lines in hydrogen that n_f = _______.

A) 1
B) 2
C) 3
D) 4
E) 5

Question 41

What is the ionization energy of the hydrogen atom in the n = 2 state?

A) 13.6 eV
B) -13.6 eV
C) 3.40 eV
D) -3.40 eV
E) -1.51 eV

Question 42

What is the radius of the ground state of He⁺?

A) 0.0529 nm
B) 0.193 nm
C) 0.0265 nm
D) 0.106 nm
E) 0.212 nm

Question 43

As a result of experiments involving alpha particle scattering,__________ proposed the nuclear model of the atom.

A) Einstein
B) Bohr
C) Rutherford
D) Planck
E) Feynman

Question 44

The minimum energy that a photon must have to undergo pair production is

A) 0.511 MeV.
B) 1.022 MeV.
C) 2.044 MeV.
D) 0.256 MeV.
E) any amount more than zero.

Question 45

What is the wavelength of a photon emitted when an electron in hydrogen goes from the n = 4 state to the n = 1 state?

A) 323 nm
B) 156 nm
C) 121 nm
D) 103 nm
E) 97.3 nm

Question 46

PET,the diagnostic method,stands for

A) patterned electron technique.
B) positron emission tomography.
C) proton-electron transmission.
D) penetrating emission technique.
E) None of these choice are correct.

Question 47

What is the kinetic energy of an electron in the ground state of hydrogen?

A) 0.000
B) 13.6 eV
C) 6.80 eV
D) 27.2 eV
E) 1.88 eV

Question 48

The orbits of the electron in the Bohr model of the hydrogen atom are those in which the electron's _______________ is quantized in integral multiples of h/2 $\pi$ .

A) kinetic energy
B) potential energy
C) total energy
D) linear momentum
E) angular momentum

Question 49

What is the highest energy of a photon in the Balmer series?

A) 1.89 eV
B) 3.40 eV
C) 1.51 eV
D) 0.94 eV
E) 0.66 eV

Question 50

The radius of the Bohr orbit for hydrogen with n = 3 is ______ time(s)that for the orbit with n = 1.

A) 1/3
B) 3
C) 6
D) 9
E) 18

Question 51

How many emission lines are possible for atomic hydrogen gas with atoms excited to the n = 4 state?

A) 1
B) 2
C) 4
D) 5
E) 6

Question 52

If pair production of muon-antimuon pair can occur for photons of 5.85 fm or less,what is the mass of a muon?

A) 212 MeV/c²
B) 106 MeV/c²
C) 424 MeV/c²
D) 0.511 MeV/c²
E) 1.02 MeV/c²

Question 53

If a hydrogen atom in the ground state absorbs a 20.0 eV photon,what kinetic energy of the electron results?

A) this cannot happen
B) 20.0 eV
C) 13.6 eV
D) 6.40 eV
E) 33.6 eV

Question 54

The kinetic energy of an electron in orbit in hydrogen is _______ times its potential energy.

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

Question 55

The potential energy of an electron in the ground state of the hydrogen atom is _________.

A) 0.000
B) -13.6 eV
C) -27.2 eV
D) 13.6 eV
E) 27.2 eV

Question 56

Which of the following statements is true?

A) All the photons of the Lyman series are in the ultraviolet.
B) Some of the photons of the Lyman series are in the visible.
C) Some of the photons of the Lyman series are in the infrared.
D) All of the Balmer series are in the visible.
E) All of these statements are false.

Question 57

What is the least-energy photon that a hydrogen atom in the ground state can absorb?

A) any energy
B) 13.6 eV
C) 10.2 eV
D) 3.40 eV
E) 1.90 eV

Question 58

For the ion He⁺,what is the energy of the ground state?

A) -13.6 eV
B) -27.2 eV
C) -54.4 eV
D) -6.80 eV
E) -3.40 eV

Question 59

What is the energy of a photon emitted in a transition from the n = 3 state to the n = 2 state in He⁺?

A) 15.1 eV
B) 7.56 eV
C) 3.78 eV
D) 2.12 eV
E) 1.89 eV

Question 60

A photon that is emitted during a transition in hydrogen from the n = 27 state to the n = 2 state is in which of the following series?

A) Lyman
B) Balmer
C) Paschen
D) Brackett
E) All of these choices are correct.

Question 61

Electrons are used to produce X-rays by allowing a beam of electrons to strike a heavy metal surface.When the intensity of the electron beam is increased,this results in:

A) X-rays being produced having longer wavelength
B) X-rays being produced having higher energy
C) More X-rays produced per unit time
D) Faster X-rays being produced

Question 62

Ultraviolet light is shone on a piece of metal that has a known work function,and electrons are observed being produced through the interaction of the light with the metal.The lamp that produces the light is now replaced with a lamp of the same intensity,but which produces photons having a longer wavelength.What difference is observed in the number of electrons produced per unit time?

A) The same number are produced.
B) More are produced.
C) Without knowing more about the wavelengths used,one cannot answer.
D) Fewer are produced.

Question 63

What is the maximum wavelength photon that can produce a pair of tau particles (rest mass 1.777 GeV/c²) by pair production?

A) 8.72 $\times$ 10^-8 nm
B) 3.49 $\times$ 10^-7 nm
C) 6.98 $\times$ 10^-7 nm
D) 1.74 $\times$ 10^-7 nm

Question 64

Dark lines that appear in the spectra observed in stellar atmospheres indicate the fact that

A) atoms that would produce light of the darkened frequency bands aren't present in the atmosphere.
B) atoms are present in the atmosphere that have electrons that are absorbing photons of those frequencies.
C) atoms are present in the atmosphere that have electrons that are emitting photons of those frequencies
D) atoms that would produce light of the darkened frequency bands are forbidden from doing so because of quantum effects.

Question 65

Light having a wavelength equal to the peak wavelength of a star of what temperature can produce photoelectrons from manganese ( $\phi$ = 4.1 eV)

A) 960 K
B) 23000 K
C) 9600 K
D) 96000 K
E) 2300 K

Question 66

Ultraviolet light is shone on a piece of metal that has a known work function,and electrons are observed being produced through the interaction of the light with the metal.The lamp that produces the light is now replaced with a lamp of the same intensity,but which produces photons having a shorter wavelength.What difference is observed in the number of electrons produced per unit time?

A) The same number are produced.
B) Fewer are produced .
C) Without knowing more about the wavelengths used,one cannot answer.
D) More are produced.

Question 67

The energy of the electron in an atom depends primarily on

A) the spin magnetic quantum number s
B) the radial quantum number n
C) the orbital angular momentum quantum number l
D) the magnetic quantum number m

Question 68

Electrons are used to produce X-rays by allowing a beam of electrons to strike a heavy metal surface.What is true about the wavelengths of the characteristic X-rays that are produced in such a situation?

A) There is a continuous range of wavelengths produced,up to a maximum that depends on the energy of the electron beam used.
B) There is a single wavelength of X-ray produced that depends on the energy of the electron beam used.
C) There are a few specific wavelengths that are produced for a given metal and their wavelength is independent of the energy of the electron beam used.
D) There is a continuous range of wavelengths produced,down to a minimum that depends on the energy of the electron beam used.

Question 69

A Compton scattering experiment is performed in which the scattered photons have a maximum energy of 17.2 keV.What was the incident energy of the photons used in this experiment?

A) 16.6 keV
B) 18.5 keV
C) 16.1 keV
D) 17.8 keV

Question 70

A photocell is a device that operates using the photoelectric effect.What metal should be used if it is desired that the photocell operate using visible light?

A) manganese ( $\phi$ = 4.1 eV)
B) gadolinium ( $\phi$ = 2.90 eV)
C) cesium ( $\phi$ = 2.14 eV)
D) beryllium ( $\phi$ = 4.98 eV)

Question 71

Electrons are used to produce X-rays by allowing a beam of electrons to strike a heavy metal surface.When the speeds of the electrons in the beam is increased,this results in:

A) X-rays being produced having higher energies
B) X-rays having longer wavelengths being produced
C) Faster X-rays being produced
D) More X-rays being produced per unit time

Question 72

Electrons are used to produce X-rays by allowing a beam of electrons to strike a heavy metal surface.What is true about the wavelengths of the bremsstrahlung X-rays that are produced in such a situation?

A) There are a few specific wavelengths that are produced for a given metal and their wavelength is independent of the energy of the electron beam used.
B) There is a single wavelength of X-ray produced that depends on the energy of the electron beam used.
C) There is a continuous range of wavelengths produced,down to a minimum that depends on the energy of the electron beam used.
D) There is a continuous range of wavelengths produced,up to a maximum that depends on the energy of the electron beam used.

Question 73

Which of the following did the planetary model of the atom fail to explain?

A) the relationship between orbital radius and energy
B) why alpha particles in Rutherford's experiment deflected at high angles when incident on atomic foils
C) why most alpha particles in Rutherford's experiment passed with little deflection through atomic foils
D) why electrons in atoms don't radiate all their energy away rapidly

Question 74

Ultraviolet light is shone on a piece of metal that has a known work function,and electrons are observed being produced through the interaction of the light with the metal.The lamp that produces the light is now replaced with a lamp of the same intensity,but which produces photons having a shorter wavelength.Which of the below differences is observed?

A) Fewer electrons per unit time are produced.
B) More electrons per unit time are produced.
C) Nothing changes at all.
D) Electrons with a higher maximum energy are observed.
E) Electrons with lower maximum energy are observed.

Question 75

An electron and positron,each having kinetic energy 10 MeV,annihilate and produce two photons.What wavelength is each photon?

A) 0.124 pm
B) 0.118 pm
C) 0.248 pm
D) 0.062 pm
E) need more information

Question 76

X-rays of wavelength 0.240 nm are scattered from a free electron at rest and the resulting scattered photons have wavelength 0.244 nm.Through what angle did these photons scatter from the initial direction?

A) 130 $^{\circ}$
B) 80 $^{\circ}$
C) such scattering is impossible
D) 34 $^{\circ}$