The electric field of light wave is given as `vec(E)=10^(-3)cos((2 pi x)/(5xx10^(-7))-2pi xx 6xx10^(14)t) hat(x) (N)/(C)`. This light falls on a metal plate of work function 2 eV. The stopping potential of the photo-electrons is:
Given, E (in eV) `= (12375)/(lambda ( "in" Å ))`

Options

A. 2.0 V
B. 0.72 V
C. 0.48 V
D. 2.48 V

Answer

C

Explanation

Clearly `(2pi)/(lambda)=(2 pi)/(5xx10^(-7)) " " :. Lambda=5000 Å`
`:.E=eV+ phi rArr V = (12375)/(5000)-2=0.475 V ~~ 0.48 ` volt.