Question

Light of wavelength $\lambda$shines on a metal surface with intensity X, the metal emits Y electrons per second of average energy Z. If X is doubled, Y , Z

• A. halved
• B. remains same
• C. doubles
• D. quadruples

Answer 1

Answer: (B), (C)

doubles

In photoelectric effect:

$\to$ The number of electrons ejected are proportional to intensity of light

$\to$ Intensity does not affect average energy of photo-electrons.

Now, when intensity is doubled, the number of electrons emitted per second (Y) will be doubled.
Further - there will be no effect on the average energy of photo-electrons (Z).

$\Rightarrow$ Y $\to$ Doubled

Z $\to$ Same