How do you calculate the energy of a photon with an electromagnetic wave of wavelength 420 nm?

1 Answer
Jun 6, 2017

The energy of a photon of frequency nu is given by,

E = hnu where h is the Planck's constant.

Also, we have the general relationship for waves,

nulamda = c where lamda is the wavelength and c is the speed of the wave.

This gives, nu = c/(lamda)

Plugging it into the expression for energy,

E = hc/(lamda)

Thus, plugging in the numerical values,

E = 4.73 * 10^(-19) J Or E = 2.95 eV