# Worksheet: Photon Momentum

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

Q1:

What is the momentum of a gamma-ray photon with a wavelength of m? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A kg⋅m/s
• B kg⋅m/s
• C kg⋅m/s
• D kg⋅m/s
• E kg⋅m/s

Q2:

What is the momentum of a photon that has a wavelength of 500 nm? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A kg⋅m/s
• B kg⋅m/s
• C kg⋅m/s
• D kg⋅m/s
• E kg⋅m/s

Q3:

A solar sail is a proposed method of spacecraft propulsion that uses the momentum of photons as a source of thrust. When photons hit the sail, they are absorbed and their momentum is transferred to the sail. If laser light with a wavelength of 200 nm is used to propel the sail, how many photons must hit the sail for it to gain 1 kg⋅m/s of momentum? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A photons
• B photons
• C photons
• D photons
• E photons

Q4:

A laser produces photons, each with a frequency of Hz. What magnitude of momentum does producing these photons impart on the laser? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

Q5:

What is the ratio of the momentum of a photon to its frequency? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A
• B
• C
• D
• E

Q6:

The the wavelength of a photon, the its momentum is. The the frequency of a photon, the its momentum is.

• Ashorter, larger, lower, larger
• Bshorter, larger, higher, larger
• Clonger, larger, higher, smaller
• Dlonger, larger, higher, larger
• Eshorter, smaller, higher, smaller

Q7:

What is the momentum of an ultraviolet photon with a frequency of 1.5 PHz? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A kg⋅m/s
• B kg⋅m/s
• C kg⋅m/s
• D kg⋅m/s
• E kg⋅m/s

Q8:

The momentum of a photon is to its wavelength and to its frequency.

• Ainversely proportional, inversely proportional
• Binversely proportional, proportional
• Cinversely proportional, equal
• Dproportional, inversely proportional
• Eproportional, proportional

Q9:

A low-frequency radio wave has a frequency of 200 kHz. What is the momentum of a radio-wave photon with this frequency? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A kg⋅m/s
• B kg⋅m/s
• C kg⋅m/s
• D kg⋅m/s
• E kg⋅m/s

Q10:

What is the wavelength of a photon that has a momentum of kg⋅m/s? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.

• A 0.754 nm
• B 1.51 nm
• C 0.663 nm
• D 1.33 nm
• E 2.65 nm

Q11:

A photon has a momentum of kg⋅m/s. What is the frequency of the photon? Use a value of J⋅s for the Planck constant. Give your answer to 3 significant figures.