Question

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled ?

(1) zero

(2) doubled

(3) four times

(4) one-fourth

Answer 1

Ans : (1) zero

Explanation :

When the frequency of incident light is halved of its original value i.e. 1.5V₀ then it becomes less than the threshold value. In that case no photoelectric effect takes place. No photoelectrons would be emitted. The photoelectric current becomes zero.