A charge `+q` is placed at a distance 'd' from the centre of the uncharged metallic cube of side 'a'. The electric field at the centre of the cube due to induced charges on the cube will be

Options

A. zero
B. `(q)/(4pi in_(0)d^(2))(- hat(j))`
C. `(q)/(4pi in_(0) d^(2))(hat(j))`
D. `(q)/(4pi in_(0)(d -(a)/(2)))(- hat(j))`

Answer

B

Explanation

Net field at the centre of cube `=0`
`:. E_(1)+E_(q)=0`
`rArr E_(1)= - (q)/(4pi in_(0) d^(2))`
`:. |E_(1)|= (q)/(4pi in_(0) d^(2))`