Four equal charges Q are placed at the four corners of a square of each side 'a'. Work done in removing a charge - Q from its centre to infinity is …………….

Options

A. 0
B. `(sqrt(2)Q^(2))/(piin_(0)a)`
C. `(sqrt(2)Q^(2))/(4piin_(0)a)`
D. `(Q^(2))/(2piin_(0)a)`

Answer

B

Explanation

Potential at centre O of the sphere, `V_(0)=4[(Q)/(4piepsilon_(0))(a//sqrt(2))]`
Work done in shifting (-Q) charge from centre to infinity,
`W=-Q(V_(oo)-V_(0))QV_(0)=(sqrt(2)Q^(2))/(piepsilon_(0)a)`