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

Accepted Answer

According to Wien's displacement law, the peak wavelength of a blackbody radiation is inversely proportional to its temperature. If Star B's peak wavelength is one-third that of Star A, then Star B's temperature must be three times that of Star 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

Accepted Answer

To find the wavelength, use the formula E = hc/λ. First, convert 3.0 keV to joules: 3.0 keV = 3.0 × 10^3 eV = 3.0 × 10^3 × 1.60 × 10^-19 J = 4.8 × 10^-16 J. Then, rearrange the formula to λ = hc/E. Substitute the values: λ = (6.63 × 10^-34 J⋅s × 3.00 × 10^8 m/s) / 4.8 × 10^-16 J = 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

Accepted Answer

B

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

Accepted Answer

The peak wavelength of radiation emitted by a blackbody increases as the temperature decreases, according to Wien's displacement law.

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

Accepted Answer

The answer of Light of wavelength 6.1 × 10−⁷ m...

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

Accepted Answer

The frequency (f) can be calculated using the formula E = hf, where E is the energy of the photon and h is Planck's constant. Solving for f gives f = E/h = (6.5 × 10^-19 J) / (6.63 × 10^-34 J⋅s) = 9.8 × 10^14 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

Accepted Answer

The energy of a photon is directly proportional to its frequency, and inversely proportional to its wavelength. Red light has the longest wavelength and the lowest frequency among the given options, which means it has the least energy. Therefore, choice A) red is the best answer.

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

Accepted Answer

Interference is a property that is unique to waves and can be observed in phenomena such as diffraction and double-slit experiments. Energy, quanta, and momentum can also apply to both waves and particles.

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

Accepted Answer

The energy of a photon is given by E = hf, where h is Planck's constant and f is the frequency of the radiation.

We are given the energy of the photon as 1.3 keV, which we need to convert to Joules: 
1.3 keV × (1.60 × 10^-19 J/eV) = 2.08 × 10^-16 J

Now we can use the equation E = hf to solve for f: 
2.08 × 10^-16 J = (6.63 × 10^-34 J·s) f 
f = (2.08 × 10^-16 J) / (6.63 × 10^-34 J·s) 
f = 3.1 × 10^17 Hz

Therefore, the answer is B) 3.1 × 10^17 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

Accepted Answer

Wien's displacement law states that the peak wavelength is inversely proportional to the temperature. If the temperature is doubled, the peak wavelength is halved, changing by a factor of 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

Accepted Answer

The energy of a photon is given by E = hf, where h is Planck's constant and f is the frequency. Substituting the given values, E = (6.63 × 10^−34 J⋅s)(7.9 × 10^20 Hz) = 5.24 × 10^−13 J. Converting to MeV using 1 eV = 1.60 × 10^−19 J, we get E ≈ 3.3 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

Accepted Answer

The maximum kinetic energy of ejected electrons is given by the equation: KE_max = E_photon - Work function. Here, KE_max = 4.0 eV - 1.60 eV = 2.4 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

Accepted Answer

The answer of What is the surface temperature of a...

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

Accepted Answer

The wavelength λ can be calculated using the formula E = hc/λ. Rearranging gives λ = hc/E. Substituting the given values: λ = (6.63 × 10^-34 J⋅s * 3.00 × 10^8 m/s) / (4.81 × 10^-19 J) = 414 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

Accepted Answer

The answer of A helium-neon laser emits red light having...

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.

Accepted Answer

The kinetic energy of the most energetic electrons in the photoelectric effect depends on the frequency of the light and the work function of the metal, not the brightness (intensity) of the light.

Question 17

Of the following photons,which has the lowest energy?
A) visible
B) ultraviolet
C) infrared
D) microwave

Accepted Answer

Microwave photons have the lowest energy because they have longer wavelengths and lower frequencies compared to visible, ultraviolet, and infrared photons.

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)

Accepted Answer

We know that the maximum kinetic energy of photoelectrons emitted is given by E= hf - Φ, where hf is the energy of the incident photon and Φ is the work function of the surface.

For surface #1: E = hc/λ - Φ = 11ea7a51_63b0_c4bf_89bd_718196db6d1c_TB5259_11
For surface #2: E = hc/λ - Φ = 11ea7a51_63b0_c4c2_89bd_6356bf2e6bc9_TB5259_11

As the wavelength of the incident photons is decreasing, their energy is increasing (inverse relationship of E=hc/λ). Therefore, the maximum kinetic energy of photoelectrons emitted by both surfaces will increase.

Comparing the two expressions for E, we see that E for surface #1 is greater than E for surface #2. Therefore, the statement in choice B is true.

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

Accepted Answer

The answer of What is the wavelength of a monochromatic...

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

Accepted Answer

First, calculate the energy of a single photon using the formula $E = \frac{hc}{\lambda}$, where $h = 6.63 \times 10^{-34} \, \text{J} \cdot \text{s}$, $c = 3.00 \times 10^{8} \, \text{m/s}$, and $\lambda = 590 \times 10^{-9} \, \text{m}$. Then, divide the total power output by the energy per photon to find the number of photons emitted per second.

Quiz 28: Atomic Physics: Part A

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?

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)

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)

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

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)

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

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

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

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)

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?

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)

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?

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)

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 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)

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

Of the following photons,which has the lowest energy?

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?

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 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)

Quiz 28: Atomic Physics: Part A

Star A has the peak of its blackbody radiation at λA.Star B has its peak at λB,which is one-third that of λA.If Star A's surface temperature is TA,how does the surface temperature TB of Star B compare?

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)

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)

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

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)

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