Two identical photocathodes receive light of frequencies `f_1` and `f_2`. If the velocities of the photo electrons (of mass m ) coming out are respectively `v_1` and `v_2` then

Options

A. `v_1-v_2=[(2h)/m(f_1-f_2)]^(1//2)`
B. `v_1^2-v_2^2=(2h)/m(f_1-f_2)`
C. `v_1+v_2=[(2h)/m(f_1+f_2)]^(1//2)`
D. `v_1^2+v_2^2=(2h)/m(f_1+f_2)`