Electric charges of `+ 10 mu C, + 5 mu C, - 3 mu C and + 8 mu C` are placed at the corners of a square of side `sqrt2m`. 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

As shown in Figure distance of centre point O from any vertex of square ABCD
`r = a/sqrt2 = sqrt2/sqrt2 =1m`
` :.` Potential at O, `V = 1/( 4 pi epsi_0.r)[q_1 + q_2 + q_3 + q_4]`
` = (9 xx 10^9)/1 [ 10 + 5- 3 + 8] xx 10^(-6) = 1.8 xx 10^5 V`