Question

• Effect of intensity on photoelectrons
  • What effect does changing the light intensity have on the maximum energy of the photoelectrons and what evidence supports your answer?
  • What effect does changing the light intensity have on the charging time and why?
• Effect of frequency on photoelectrons
  • What effect does changing the frequency of the light have on the maximum energy of the photoelectrons and what evidence supports your answer?
  • Are any of the frequencies used below the threshold (work function) of the apparatus and how do you know?

Answer 1

Effect of intensity on photoelectron :-

As intensity will increase then no. Of photons will increase but the energy of each photon will be same . So more photons will remove more photoelectron but energy of each photoelectron will be same .

So maximum energy of photoelectron will be independent of intensity of light . In evidence stopping potential will not change with the change of potential energy.

Now as photoelectron will be more in numbers so charge will be more so charging time will decrease with increase of intesity

B) Effect of frequency on photoelectron :- as we increase frequency of light energy of photon will increase do as it collide with photoelectron, photoelectron will have more kinetic energy . So maximum energy of photoelectron will be directly proportional to the frequency of light.

In evidence , stoping potential has to be increased if frequency of light is increased .

C) if we use any of the frequency which is below than threshold frequency no photoelectron will be removed so no current will flow , so we will be able to detect that frequency is below threshold frequency