A photon is scattered from an initially stationary electron within a metal. How does the frequency of the photon change upon scattering?

The frequency of the photon decreases upon scattering

Explanation:

Here we note that when a photon is scattered by a charged particle, it is referred to as Compton scattering.

Compton scattering results in a reduction of the energy of the photon and hence an increase in the wavelength (from λ to λ') of the photon known as Compton effect.

Therefore, since the wavelength increases, we have from

λf = λ'f' = c

f = c/λ

Where:

f and f' = The frequency of the motion of the photon before and after the scattering

c = Speed of light (constant)

We have that the frequency, f, is inversely proportional to the wavelength, λ as follows;

f = c/λ

As λ = increases, and c is constant, f decreases, therefore, the frequency of the photon decreases upon scattering.

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