Hydrogen has a red emission line at 656.3 nm, what is the energy and frequency of a photon of this light? note: planck's constant = 6.626 x 10–34 j·s, speed of light = 2.998 x 108 m/

- Energy = and frequency = .

Solution:- The wavelength is given as 656.3 nm and it asks to calculate energy and frequency of a photon of this light. When the wavelength is given then the energy is calculated by using the equation:

where, E is energy, h is planck's constant, c is speed of light and is the wavelength.

Wavelength is given in nm and for calculations of energy we need it in m.

Let's plug in the values in the equation to calculate energy:

E =

Frequency is calculated for the given wavelength using the equation:

let's plug in the values in the equation:

So, the energy of the photon for given wavelength is and the frequency is .

it is the most commonly accepted one