The red line of the hydrogen emission spectrum has a wavelength of 656.1 nm. Calculate the energy of one photon

The formula we can use here is the Plancks equation:

E = h c / ʎ

where h is Plancks constant = 6.626 * 10-34 m2 kg / s, c is speed of light = 3 x 10^8 m/s and ʎ is wavelength = 656.1 x 10^-9 m

Therefore E is:

E = (6.626 * 10-34 m2 kg / s) * (3 x 10^8 m/s) / 656.1 x 10^-9 m

E = 3.03 x 10^-19 J