Deck 28: Atomic Physics: Part A

Question 1

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

Answer 1

T_B = 3T_A

Question 2

If a quantum of radiation has an energy of 3.0 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) 0.62 nm
B) 0.32 nm
C) 0.41 nm
D) 1.02 nm

Answer 2

0.41 nm

Question 3

Blue light (λ = 460 nm)is incident on a piece of potassium (W = 2.45 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) 1.0 eV
B) 0.25 eV
C) 0.50 eV
D) 4.9 eV

Answer 3

0.25 eV

Question 4

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 5

Light of wavelength 6.1 × 10−⁷ m has an energy of: (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s)

A) 3.1 × 10−¹⁹ J
B) 1.5 × 10−¹⁹ J
C) 1.7 × 10−¹⁹ J
D) 3.3 × 10−¹⁹ J

Question 6

What is the frequency of monochromatic light where the photon energy is 6.5 × 10−¹⁹ J? (h = 6.63 × 10−³⁴ J⋅s)

A) 2.2 × 10¹⁴ Hz
B) 9.8 × 10¹⁴ Hz
C) 4.4 × 10¹⁴ Hz
D) 8.3 × 10¹⁴ Hz

Question 7

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

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

Question 8

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 9

A quantum of radiation has an energy of 1.3 keV.What is its frequency? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.60 × 10−¹⁹ J)

A) 6.3 × 10¹⁷ Hz
B) 3.1 × 10¹⁷ Hz
C) 4.8 × 10¹⁷ Hz
D) 7.2 × 10¹⁷ Hz

Question 10

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

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

Question 11

What is the energy of a photon whose frequency is 7.9 × 10²⁰ Hz? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.60 × 10−¹⁹ J)

A) 5.0 MeV
B) 3.3 MeV
C) 1.6 MeV
D) 2.5 MeV

Question 12

If a monochromatic light beam with quantum energy value of 4.0 eV is incident upon a photocell where the work function of the target metal is 1.60 eV,what is the maximum kinetic energy of ejected electrons?

A) 4.6 eV
B) 4.8 eV
C) 2.4 eV
D) 1.4 eV

Question 13

What is the surface temperature of a distant star (which emits light as if it were a blackbody)where the peak wavelength is 456 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) 5100 K
B) 4510 K
C) 6040 K
D) 6360 K

Question 14

What is the wavelength of a monochromatic light beam,where the photon energy is 4.81 × 10−¹⁹ J? (h = 6.63 × 10−³⁴ J⋅s,c = 3.00 × 10⁸ m/s,and 1 nm = 10−⁹ m)

A) 354 nm
B) 414 nm
C) 787 nm
D) 398 nm

Question 15

A helium-neon laser emits red light having a wavelength of 632.8 nm and a power of 10 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) 4.8 × 10¹⁷
B) 1.6 × 10¹⁵
C) 3.2 × 10¹⁶
D) 2.6 × 10¹⁸

Question 16

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

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

Question 17

Of the following photons,which has the lowest energy?

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

Question 18

Surface #1 has work function
,and when bombarded with photons of wavelength
Emits photoelectrons with maximum energy
)Surface #2 has work function
,and when bombarded by photons of wavelength
Emits photoelectrons with maximum energy
)If
,then which of the following must be true?

A)

B)
for surface #1 is greater than
for surface #2.
C)
for surface #2 is greater than
for surface #1.
D)

Question 19

What is the wavelength of a monochromatic light beam,where the photon energy is 2.00 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) 414 nm
B) 1243 nm
C) 311 nm
D) 622 nm

Question 20

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 21

What is the maximum velocity of a photoelectron emitted from a surface with work function 5.22 eV when illuminated by 200-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) 800,000 m/s
B) 212,000 m/s
C) 653,000 m/s
D) 591,000 m/s

Question 22

Of the following energies for photons,which is the least energy that could result in photoelectron production if the work function is 1.60 eV?

A) 1.50 eV
B) 6.01 eV
C) 2.90 eV
D) 3.50 eV

Question 23

Starting from rest,an electron accelerates through a potential difference of 67 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) 1.1 × 10−¹⁰ m
B) 1.5 × 10−¹⁰ m
C) 1.9 × 10−¹⁰ m
D) 2.3 × 10−¹⁰ m

Question 24

An electron and an alpha particle (a helium-4 nucleus)each have the same non-relativistic speed.Which has the greatest kinetic energy,and which has the shortest de Broglie wavelength?

A) the alpha particle,the alpha particle
B) the alpha particle,the electron
C) the electron,the alpha particle
D) the electron,the electron

Question 25

An electron microscope operates with electrons of kinetic energy 100 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) 5.49 × 10−¹² m
B) 7.14 × 10−¹¹ m
C) 9.28 × 10−¹⁰ m
D) 3.88 × 10−¹² m

Question 26

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 27

How much energy (in eV)does a photon of 500-nm light 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) 1.78 eV
B) 2.48 eV
C) 1.24 eV
D) 3.11 eV

Question 28

A proton (mass = 1.67 × 10−²⁷ kg)has a kinetic energy of 1.00 MeV.If its momentum is measured with an uncertainty of 2.00%,what is the minimum uncertainty in its position? (h = 6.63 × 10−³⁴ J⋅s and 1 eV = 1.6 × 10−¹⁹ J)

A) 9.08 × 10−¹⁴ m
B) 1.14 × 10−¹³ m
C) 5.64 × 10−¹⁴ m
D) 2.28 × 10−¹³ m

Question 29

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

A) 1/4
B) 1/16
C) 16
D) 4

Question 30

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

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

Question 31

If the measured momentum of an electron is 3.20 × 10−²⁷ kg⋅m/s with an uncertainty of 4.8 × 10−²⁸ kg⋅m/s,what is the minimum uncertainty in the position? (h = 6.63 × 10−³⁴ J⋅s)

A) 0.63 × 10−⁴ m
B) 2.2 × 10−⁷ m
C) 3.3 × 10−⁶ m
D) 1.1 × 10−⁷ m

Question 32

What is the de Broglie wavelength for a proton (m = 1.67 × 10−²⁷ kg)moving at a speed of 3.0 × 10⁶ m/s? (h = 6.63 × 10−³⁴ J⋅s)

A) 0.33 × 10−¹³ m
B) 1.3 × 10−¹³ m
C) 0.66 × 10−¹³ m
D) 2.0 × 10−¹³ m

Question 33

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 34

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

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

Question 35

If an electron has a measured wavelength of 1.20 × 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) 209 eV
B) 55.0 eV
C) 105 eV
D) 147 eV

Question 36

The de Broglie wavelength of a 0.060-kg golf ball is 3.56 × 10−³⁴m.What is its speed? (h = 6.63 × 10−³⁴ J⋅s)

A) 31 m/s
B) 15 m/s
C) 26 m/s
D) 48 m/s

Question 37

What is the energy of a photon that has the same wavelength as a 24 eV electron? (h = 6.63 × 10−³⁴ J⋅s,m_e = 9.11 × 10−³¹ kg)

A) 24 eV
B) 14 × 10^-16 eV
C) 3.5 keV
D) 5.0 keV

Question 38

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