Could you use a highly intense beam of red light to eject electrons from the surface of a metal?

1 Answer
Apr 30, 2016

I would say no but...

Explanation:

The photo-emission of electrons depends upon frequency and not intensity.
You can shine a very intense light and not emit any electron because the energy of the light is not "right"!
The energy comes in packets called photons and depends upon Frequency #f# as:
#E=hf#
(#h# is a constant)

Red light has a comparative low frequency (compared to blue for example) so its photons will carry little energy and probably they will not be able to communicate enough energy to the electrons of the metal so that they can get free.

Anyway you may check the "Work Function" of various metals (tabulated in the literature) to see if there is a metal that can emit with red light (I do not think it exists, but it is only my opinion based upon my remembrance of my old school days!).