Question 1

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

Accepted Answer

The work function is a property of the material and does not depend on the wavelength of the incident light.

Question 2

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

Accepted Answer

The ultraviolet catastrophe refers to the classical physics prediction that a black body would emit infinite energy at ultraviolet frequencies, which was not observed in reality.

Question 3

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

C

Question 4

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 5

Light of wavelength 6.1 *10^-⁷ m has an energy of: (h = 6.63 *10^-³⁴J.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 has...

Question 6

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

The answer of According to Wien's displacement law, if the...

Question 7

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 = 10F1F1F1S1^-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. Solving for λ 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 8

Of photons of red, yellow, light, and blue light, which photons have the least energy?
A) red
B) blue
C) green
D) yellow

Accepted Answer

Red light has the longest wavelength and lowest frequency, and therefore the least energy.

Question 9

If a blackbody is at 2000° C, what will be the peak wavelength emitted?
A) 1.67 $\mu$m
B) 1.28 $\mu$m
C) 0.679 $\mu$m
D) 1.45 $\mu$m

Accepted Answer

The peak wavelength emitted by a blackbody can be calculated using Wien's Displacement Law: λ_max = b/T, where b is Wien's constant (approximately 2898 μm·K). Converting 2000°C to Kelvin gives 2273 K. Using the formula, λ_max ≈ 2898 μm·K / 2273 K ≈ 1.275 μm. The closest option is 0.679 μm, which seems to be a mistake in the options provided.

Question 10

If a quantum of radiation has an energy of 3.0 keV, what is its wavelength? (h = 6.63 *10^-³⁴J.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 x 10^3 eV = 3.0 x 10^3 x 1.60 x 10^-19 J = 4.8 x 10^-16 J. Then, rearrange the formula to λ = hc/E. Substitute the values: λ = (6.63 x 10^-34 J·s x 3.00 x 10^8 m/s) / 4.8 x 10^-16 J = 0.41 nm.

Question 11

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

The answer of Surface #1 has work function  ,...

Question 12

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 $\mu$m). (1 nm = 10 ^- ⁹m = 10^-3$\mu$m) 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 13

Blue light will not eject electrons from a certain metal; however, which one of the following may possibly eject electrons from that metal?
A) red
B) green
C) infrared
D) ultraviolet

Accepted Answer

Ultraviolet light has a higher frequency and energy than blue light, which may provide enough energy to overcome the work function of the metal and eject electrons.

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

Accepted Answer

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

Question 15

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 *10¹⁴Hz B) 9.8 * 10¹⁴ Hz C) 4.4 *10¹⁴ Hz D) 8.3 *10¹⁴ Hz

Accepted Answer

The frequency of light can be calculated using the formula E = h*f, where E is the energy of the photon, h is Planck's constant, and f is the frequency. Solving for f gives f = E/h. Substituting the given values, f = (6.5 x 10^-19 J) / (6.63 x 10^-34 J·s) = 9.8 x 10^14 Hz.

Question 16

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 characteristic of wave property. When waves interact, they can either reinforce each other or cancel each other out, resulting in interference patterns. Particle properties are not known to display interference. The other options, energy, quanta, and momentum, can apply to both wave and particle properties.

Question 17

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 the quantum of radiation is given as 1.3 keV, which is equivalent to 1.3 x 1.60 x 10^-16 J. Using the formula E = hν, where E is energy and h is Planck's constant, we can solve for frequency ν: ν = E/h. Substituting the values, ν = (1.3 x 1.60 x 10^-16 J) / (6.63 x 10^-34 J·s) = 3.1 x 10^17 Hz.

Question 18

Star A has the peak of its blackbody radiation at $\lambda$_A. Star B has its peak at $\lambda$_B, which is one-third that of $\lambda$_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 = 3 T_A C) T_B = 9 T_A D) T_B = T_A/3

Accepted Answer

According to Wien's Law, the peak wavelength is inversely proportional to the temperature. If Star B's peak wavelength is one-third of Star A's, then Star B's temperature is three times that of Star A.

Question 19

Classical theories predict that most of the energy from a blackbody should be radiated:
A) at the wavelength given by Wien's displacement law.
B) as thermal radiation in the infrared region.
C) a blackbody should not radiate.
D) as ultraviolet light.

Accepted Answer

The answer of Classical theories predict that most of the...

Question 20

Planck's quantum theory is compatible with the experimental data related to which of the following?
A) line spectra emitted by hydrogen gas
B) the photoelectric effect
C) blackbody radiation
D) all of these choices

Accepted Answer

Planck's quantum theory is compatible with all the mentioned phenomena: line spectra, the photoelectric effect, and blackbody radiation, as it explains the quantization of energy levels and the emission and absorption of energy in discrete amounts.

Quiz 28: Quantum Theory

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

The ultraviolet catastrophe predicts that:

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 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)

Light of wavelength 6.1 10^-⁷ m has an energy of: (h = 6.63 10^-³⁴J.s, c = 3.00 * 10⁸ m/s)

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 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)

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

If a blackbody is at 2000° C, what will be the peak wavelength emitted?

If a quantum of radiation has an energy of 3.0 keV, what is its wavelength? (h = 6.63 10^-³⁴J.s, 1 eV = 1.60 10^-¹⁹ J, c = 3.00 *10⁸ m/s, and 1 nm = 10^-⁹ m)

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 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 $\mu$ m) . (1 nm = 10 ^- ⁹m = 10^-3 $\mu$ m)

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

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

What is the frequency of monochromatic light where the photon energy is 6.5 10^-¹⁹ J? (h = 6.63 10^-³⁴ J.s)

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)

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

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

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