Question

According to the classical wave picture of light, how would the current versus potential (between the plates) graph vary upon varying intensity?

• A.
• B.
• C.
• D.

Answer 1

The correct option is D

Second quadrant: The stopping potential is a direct measure of the maximum kinetic energy found among the photoelectrons. In classical model if intensity is decreased, the energy delivered to each electron is reduced, which will consequentially decrease the maximum kinetic energy. Hence,

• the stopping potential should become less negative with decreasing intensity, in the wave picture.

In all the four options I₃is the lowest intensity so the stopping potential corresponding to it should be the least in magnitude.

We see that in option d.

P.S: Although (d) is the correct answer for , it is very far from the truth , as you have seen. This only points to incompleteness in the wave theory of light.