Write any three experimental observations of photoelectric effect

Explanation

(i) The photoelectric emission is an instantaneous process.
(ii) For every photo emissive material, there exists a minimum frequency of radiation below which there is no photoelectric emission. This minimum frequency is called threshold frequency `(v_0)`.
(iii) Above the threshold frequency, the photocurrent is directly proportional to the intensity of incident radiation.
(iv) Above the threshold frequency, the maximum kinetic energy of the photo electrons is directly proportional to the frequency of incident radiation.
(v) The photoelectric current increases with increase in collector plate voltage and reaches a saturation value.
(vi) The photocurrent decreases with increase in negative potential and reaches zero at a negative potential known as stopping potential.