In photoelectric effect light of certain frequency `( gt ` threshold frequency ) is incident on a metal surfave whereby , an `e^(-)` ( with certain K.E.) moves towards the collector plate and a flow of current is initiated . In order to stop the current flow, an opposite potential , on the two metal plates, is applied
A light of frequency `2.5xx 10^(15) Hz` is incident on a metal surface having work function 4 eV. The velocity of photoelectron is ( in cm `s^(-1))`
A. `1.5 xx 10^(6)`
B. `1.5 xx 10^(8)`
C. `2 xx 10^(8)`
D. `2.5 xx 10^(4)`
