Charges +q and -q are placed at points A and B respectively which are a distance 2L aprt,C is the mid point between A and B. The work done in moving a charge + Q along the semicircle CRD is

Options

A. `(qQ)/(4 pi epsi_(0)L)`
B. `(qQ)/(2 pi epsi_(0)L)`
C. `(qQ)/(6 pi espi_(0)L)`
D. `-(qQ)/(6 pi epsi_(0)L)`

Answer

D

Explanation

Initially

`v_1= (KQ q)/L- (KQ q)/L- (K q^2)/(2L)`
Finally,

`V_f=(kq^2)/(2L)+(2Lq)/(3L)- (KQ q)/L`
Work done =`Delta V= V_f-V_i=- (q Q)/(6 pi e_0L)`