The threshold frequency of metal is f 0 . When the light of frequency 2 f 0 is incident on the metal plate, the maximum velocity of photoelectron is v 1 . When the frequency of incident radiation is increased to 5 f 0 . the maximum velocity of photoelectrons emitted is v 2 . The ratio of v 1 to v 2 is:

Step-by-step solution

Maximum kinetic energy is related to the incident frequency f and the threshold frequency f 0 as: K max = h f - h f 0 When, f = 2 f 0 1 2 m v 1 2 = 2 h f 0 - h f 0 = h f 0           . . . 1 When, f = 5 f 0 1 2 m v 2 2 = 5 h f 0 - h f 0 = 4 h f 0         . . . 2 Hence, the ratio, v 1 v 2 = 1 2