A fixed ring of radius R is given a charge q. A charge `q_0` is brought slowly from infinity to the centre of the ring. The wrong statement is-

Options

A. work done by external agent in bringing `q_(0)` is `1/(4pi epsilon_(0)). (q q_(0))/R` when charge distribution is uniform
B. work done by external agent in bringing `q_(c)` is `1/(4piepsilon_(0)) (q q_(0))/R`
C. force on `q_(0)` at the centre is zero, when charge distribution is uniform
D. force on `q_(0)` at the central is zero, when one half of the ring has positive charge and other half has negative charge

Answer

D

Explanation

The potential of the centre is same whether the charge in uniformly distributed or non-uniformly distributed. Hence statement(1) and (2) are correct.
When charge on one half is +ve and other half is -ve, the field can not be zero, hence force is not zero. Statement-4 is wrong,. hence (4) is the correct option.