# Calculating Energy of a Photon Based on Wavelength

## Photon Energy Calculation

A photon has a wavelength of 547 nm. We are required to calculate the energy of the photon in joules.

**Answer:**

**Energy** = **3.63 × 10**⁻¹⁹ **Joules**

**Explanation:**

The energy contained by a photon is directly proportional to its frequency and inversely proportional to its wavelength. The smaller the wavelength, the greater the energy and vice versa.

The relation between wavelength and energy is as follows,

E = h c / λ

where

E = Energy = ?

h = Planck's Constant = 6.6262 × 10⁻³⁴ Js

c = velocity of light = 3.0 × 10⁸ ms⁻¹

λ = wavelength = 547 nm = 547 × 10⁻⁹ m

Putting the given values into the formula,

E = 6.6262 × 10⁻³⁴ Js × 3.0 × 10⁸ ms⁻¹ / 547 × 10⁻⁹ m

E = **3.63 × 10**⁻¹⁹ **Joules**

How is the energy of a photon related to its wavelength?

The energy of a photon is inversely proportional to its wavelength. This means that photon with shorter wavelength will have higher energy, and vice versa.