Three charges ,each of `+ 4 mu C` ,are placed at the corners `A,B,C` of a square `ABCD` of side `1 m`.The electric field at the centre `O` of a square `ABCD` of side `1 m`.The electric field at the centre `O` of the square is

Options

A. `7.2 xx 10^(4) N//C` towards `D`
B. `7.2 xx 10^(4) N//C` towards `B`
C. `3.6 xx 10^(4) N//C` towards `A`
D. `7.2 xx 10^(4) N//C` towards `C`

Answer

1

Explanation

`E_(A)` camcels `E_(c )`
At `O: E_(B) = (1)/(4 pi in_(0)) (q)/((d//sqrt(2))^(2))`
` = (1)/(4 pi in_(0)) (2q)/(d^(2))`
`= (9 xx 10^(9) xx 2 xx 4 xx 10^(-6))/(1^(2))`
`7.2 xx 10^(4) N//C` , towards `D`