Question

How do you calculate frequency of light?

Answer 1

I'm assuming you have been given some further information. Otherwise you can only give a range depending on which area of the spectrum it's in.

Explanation:

The most common question is using c = `f.lambda` where c is the speed of light in a vacuum and `lambda` is the wavelength. You are given velocity and wavelength.

The other one often used connects energy and frequency (E = h.f) and again you are given a value for h, Planck's constant and the photon energy, E.