Question

When a photon of light collides with a metal surface, possible number of electrons coming out is?

• A. Only one
• B. Only two
• C. Infinite
• D. Depends upon factors

Answer 1

The correct option is A Only one

When photon strikes with the electron it completely transfers it’s energy to the electron as during photoelectric experiment the threshold frequency required is used by the electron to eject from the atom which is also called the work funtion and the remaining energy in electron is kinetic energy which can be measured. Now(before collision) since photon is a particle it must have mass and thus it has energy equivalent to $E={mc}^2$ .

After collision when it completely transfers it’s energy to electron thus$E=0$

And therefore $0={mc}^2$ thus i guess photon vanishes.