A photon of energy E ejects a photoelectron from a metel surface whose work function is `phi_(0)`. If this electron enters into a unifrom magnetic field of induction B in a direction perpendicular to the field and describes a circular path of radius r, then the radius r, is given by, (in the usual notation)

Options

A. `sqrt((2m(E-W_0))/(eB))`
B. `sqrt((2m(E-W_0)eB))`
C. `sqrt(2e(E-W_0))/(mB)`
D. `sqrt((2m(E-W_0))/(eB))`

Answer

D

Explanation

`K_("max") = E-W_0`
Radius (r) = `(mv)/(eB) = (sqrt(2mK))/(eB)=(sqrt(2m(E-W_0)))/(eB)`