Four charges are placed at the corners of a square of side 10 cm as shown in figure. If q is `1 mu C`, then what will be electric field intensity at the centre of the square?

Options

A. `1.02 xx 10^7 N//C` upwards
B. `2.04 xx10^7 N//C` downwards
C. `2.04 xx10^7 N//C` upwards
D. `1.02 xx 10^7 N//C` downwards

Answer

A

Explanation

`r=a/sqrt2`
`E= (KQ)/((a//sqrt2)^2)`
`E_("net") = sqrt(E^2+E^2)= sqrt2E`
`= (KQ)/((a//sqrt2)^2)sqrt2 =(9xx10^9 xx10^(-6)xxsqrt2xx2)/((5xx10^(-2))^2)`
`= 1.02 xx10^7 ` N/C (upward)