Question

When a source of dim orange light shines on a photosensitive metal, no photoelectrons are ejected from its surface. what could be done to increase the likelihood of producing photoelectrons

Answer 1

Answer: Replace the orange light source with a higher frequency light source

Explanation:

To expel electrons from a piece of metal, the incoming light must have a minimum frequency to cause a photoelectric effect, i.e., the ejection of photoelectrons from a metal surface, which is also known as the metal's threshold frequency.

If v = frequency of incident photon and vth= threshold frequency, then,

• For v < vth, there will be no ejection of photoelectron.

• For v = vth, photoelectrons are just ejected from the metal surface, in this case, the kinetic energy of the electron ejected is zero

• For v > vth, then photoelectrons will come out of the surface along with kinetic energy

Therefore, we would have to increase the frequency of incident light so that it becomes greater than the threshold frequency of that surface, and consequently a photoelectric process takes place.