How to Calculate the Energy of One Photon of Light?

10 Jul 2021

Question:

What is the energy of one photon of light with a wavelength of 486.0 nm?

The correct answer to the following question will be "4.08 × 10⁻¹⁹ Joule".

When calculating the energy of one photon of light, we can use the formula:

Energy = Planck's constant × frequency = Planck's constant × speed of light / wavelength

Given that the wavelength is 486.0 nm, we first need to convert it to meters by dividing by 10⁹ (since 1 meter = 10⁹ nanometers). This gives us:

Wavelength = 486.0 nm = 486.0 × 10⁻⁹ meters

Plugging this value into the formula along with Planck's constant and the speed of light, we can calculate the energy of the photon:

Energy = Planck's constant × speed of light / wavelength

After performing the calculations, we find that the energy of one photon of light with a wavelength of 486.0 nm is 4.08 × 10⁻¹⁹ Joule.