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 ) `

Answer

D