Visible light has wavelengths in the range of 400 nm to 780 nm. Calculate the range of energy of the photons of visible light.
Given: wavelengths (λ) in the range of 400 nm to 780 nm
Energy of photon is =hv =
where h is plank’s constant and ν is the frequency which is 
where the c is the speed of light and{displaystyle lambda }
{displaystyle lambda } λ (Lambda) is wavelength.
Energy of photon of wavelength 780 nm=
=
Energy of photon of wavelength 400 nm=
=
∴ the range from 
to 
.
1