Worksheet: The Quantization of Electromagnetic Radiation

In this worksheet, we will practice calculating the energy of a photon given its frequency or wavelength.

Q1:

A laser emits 4 × 1 0 photons, each with a frequency of 6 × 1 0 Hz. What is the total energy radiated by the laser? Use a value of 6 . 6 3 × 1 0 J⋅s for the Planck constant. Give your answer in joules to 3 significant figures.

Q2:

Which of the following is the correct formula for the energy of a photon given its frequency, where represents the Planck constant and 𝑐 represents the speed of light?

  • A 𝐸 = 𝑓
  • B 𝐸 = 𝑓
  • C 𝐸 = 𝑐 𝑓
  • D 𝐸 = 𝑓
  • E 𝐸 = 𝑐 𝑓

Q3:

What is the difference in the energy of a 2 × 1 0 Hz photon and a 5 × 1 0 Hz photon? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant. Give your answer in joules to 3 significant figures.

  • A 1 . 3 3 × 1 0 J
  • B 3 . 3 2 × 1 0 J
  • C 3 . 1 8 × 1 0 J
  • D 6 . 2 4 × 1 0 J
  • E 3 . 4 5 × 1 0 J

Q4:

What is the wavelength of a photon that has an energy of 2 . 9 7 × 1 0 J? Use 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant and 3 . 0 0 × 1 0 m/s for the value of the speed of light in free space. Give your answer in meters to 3 significant figures.

  • A 1 . 4 9 × 1 0 m
  • B 9 . 9 8 × 1 0 m
  • C 3 . 2 4 × 1 0 m
  • D 6 . 7 0 × 1 0 m
  • E 3 6 . 2 × 1 0 m

Q5:

What is the energy of a photon that has a wavelength of 400 nm? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant and 3 . 0 0 × 1 0 m/s for the value of the speed of light in free space. Give your answer in joules to 3 significant figures.

  • A 1 . 6 6 × 1 0 J
  • B 6 . 2 3 × 1 0 J
  • C 4 . 9 8 × 1 0 J
  • D 4 . 9 7 × 1 0 J
  • E 1 . 9 9 × 1 0 J

Q6:

Photon 𝐴 has twice the frequency of photon 𝐵 . What is the ratio of the energy of photon 𝐴 to the energy of photon 𝐵 ?

Q7:

Photon A has a wavelength that is four times that of photon B. What is the ratio of the energy of photon A to the energy of photon B?

  • A 1 4
  • B1
  • C 1 2
  • D2
  • E4

Q8:

What is the frequency of a photon that has an energy of 2 . 5 2 × 1 0 J? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant. Give your answer in hertz to 3 significant figures.

  • A 1 . 9 0 × 1 0 Hz
  • B 1 . 9 5 × 1 0 Hz
  • C 3 . 8 0 × 1 0 Hz
  • D 1 . 1 × 1 0 Hz
  • E 2 . 6 3 × 1 0 Hz

Q9:

What is the difference in the energy of a blue photon, with a wavelength of 400 nm, and a red photon, with a wavelength of 700 nm? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant and 3 . 0 0 × 1 0 m/s for the value of the speed of light in free space. Give your answer in joules to 3 significant figures.

  • A 4 . 3 2 × 1 0 J
  • B 2 . 8 4 × 1 0 J
  • C 3 . 2 5 × 1 0 J
  • D 4 . 9 7 × 1 0 J
  • E 2 . 1 3 × 1 0 J

Q10:

What is the frequency of a photon that has an energy of 3.00 eV? Use 4 . 1 4 × 1 0 eV⋅s for the value of the Planck constant. Give your answer in hertz to 3 significant figures.

  • A 6 . 9 8 × 1 0 Hz
  • B 1 . 3 8 × 1 0 Hz
  • C 5 . 3 2 × 1 0 Hz
  • D 3 . 2 5 × 1 0 Hz
  • E 7 . 2 5 × 1 0 Hz

Q11:

What is the energy of a photon that has a frequency of 5 × 1 0 Hz? Use 4 . 1 4 × 1 0 eV⋅s for the value of the Planck constant. Give your answer in electron volts to 3 significant figures.

Q12:

What is the energy of a photon that has a frequency of 5 . 5 0 × 1 0 Hz? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant. Give your answer in joules to 3 significant figures.

  • A 3 . 6 5 × 1 0 J
  • B 8 . 3 0 × 1 0 J
  • C 1 . 2 1 × 1 0 J
  • D 1 . 3 3 × 1 0 J
  • E 1 . 5 3 × 1 0 J

Q13:

A laser emits light with a wavelength of 200 nm. How many photons must be emitted by the laser for the amount of energy emitted to be 1 J? Use a value of 6 . 6 3 × 1 0 J⋅s for the value of the Planck constant and 3 . 0 0 × 1 0 m/s for the value of the speed of light in free space. Give your answer to 3 significant figures.

  • A 3 . 2 × 1 0
  • B 1 . 3 6 × 1 0
  • C 9 . 9 5 × 1 0
  • D 8 . 3 2 × 1 0
  • E 1 . 0 1 × 1 0

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