Question

How does the intensity affect the photoelectric current?

(a) As intensity increases, the photoelectric effect increases

(b) As the intensity increases, the photoelectric effect decreases

(c) As the intensity decreases, the photoelectric effect becomes twice

(d) No effect

This question was addressed to me in an interview for job.

This intriguing question originated from PhotoElectric Effect topic in portion Quantum Physics of Engineering Physics I

Answer 1

The correct option is (a) As intensity increases, the photoelectric effect increases

The best explanation: Since each incident photon ejects one photoelectron from a metal surface, therefore, the number of photoelectrons emitted depends on the number of photons falling on the metal surface, which in turn depends on the intensity on the incident light.

Hence, as the intensity increases, the number of photoelectrons ejected increases and hence photoelectric current increases.