Electric charges of `+ 10 mu C, + 5mu C, - 3mu C` and `+9 mu C` are placed at the corners of a square of side `sqrt(2) m` the potential at the centre of the square is

Options

A. `1.8 V`
B. `1.8 xx 10^(6) V`
C. `1.8 xx 10^(5) V`
D. `1.8 xx 10^(4) V`

Answer

C

Explanation

Length of each side of square is `sqrt(2)m` so distance of
its centre from each corner is `(sqrt(2))/(sqrt(2)) = 1m`.
Potential at the centre
`V = 9 xx 10^(9) [(10 xx 10^(-6))/(1) + (5 xx 10^(-6))/(1) - (3 xx 10^(-6))/(1) + (8 xx 10^(-6))/(1)]`
`= 1.8 xx 10^(5) V`