# Photon Energy Equation | Problems

Photon energy (E) is the product of planck’s constant (h) and the frequency (f). Using the equation of photon energy: E = h f, the value of energy of a photon can be calculated.

Let’s solve some problems based on this equation, so you’ll get a clear idea.

## Photon Energy Practice Problems

Problem 1: Calculate the energy of a photon which is having a frequency of 4.54 × 106 Hz. (Take the value of planck’s constant, h = 6.626 × 10-34 J s)

Solution:

Given data:
Energy of a photon, E = ?
Frequency of a photon, f = 4.54 × 106 Hz
Planck’s constant, h = 6.626 × 10-34 J s

Using the equation of photon energy,
E = h f
E = 6.626 × 10-34 × 4.54 × 106
E = 30.08 × 10-28 J

Therefore, the energy of a photon is 30.08 × 10-28 J.

Problem 2: A photon has a wavelength of 450 nm. Calculate the energy of a photon. (Take the value of planck’s constant, h = 6.626 × 10-34 J s and speed of light, c = 3 × 108 m/s)

Solution:

Given data:
Wavelength of a photon, λ = 450 nm = 450 × 10-9 m
Energy of a photon, E = ?
Planck’s constant, h = 6.626 × 10-34 J s
Speed of light, c = 3 × 108 m/s

Using the equation of photon energy,
E = h c/λ
E = (6.626 × 10-34 × 3 × 108) ÷ (450 × 10-9)
E = 0.0441 × 10-17 J

Therefore, the energy of a photon is 0.0441 × 10-17 J.

Problem 3: A photon has a frequency of 2.35 × 109 Hz. Calculate the energy of a photon. (Take the value of planck’s constant, h = 6.626 × 10-34 J s)

Solution:

Given data:
Frequency of a photon, f = 2.35 × 109 Hz
Energy of a photon, E = ?
Planck’s constant, h = 6.626 × 10-34 J s

Using the equation of photon energy,
E = h f
E = 6.626 × 10-34 × 2.35 × 109
E = 15.57 × 10-25 J

Therefore, the energy of a photon is 15.57 × 10-25 J.

Problem 4: Calculate the energy of a photon which is having a wavelength of 750 nm. (Take the value of planck’s constant, h = 6.626 × 10-34 J s and speed of light, c = 3 × 108 m/s)

Solution:

Given data:
Energy of a photon, E = ?
Wavelength of a photon, λ = 750 nm = 750 × 10-9 m
Planck’s constant, h = 6.626 × 10-34 J s
Speed of light, c = 3 × 108 m/s

Using the equation of photon energy,
E = h c/λ
E = (6.626 × 10-34 × 3 × 108) ÷ (750 × 10-9)
E = 0.0265 × 10-17 J

Therefore, the energy of a photon is 0.0265 × 10-17 J.

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