An electron is projected from a distance `d` and with initial velocity `u` parallel to a uniformly charged flat conducting plate as shown. It strikes the plate after travelling a distance `l` along the direction of projection. The surface charge density of the conducting plate is equal to

Options

A. `(2d epsilon_(0) m u^(2))/(el^(2))`
B. `(2 d epsilon_(0) m u)/(el)`
C. `(d epsilon_(0) m u^(2))/(el)`
D. `(d epsilon_(0) m u)/(el)`

Answer

A

Explanation

`S=ut+1/2 a t^(2)`