Three charges, each equal to q, are placed at the three. corners of a square of side a . Find the electric field at. the fourth corner.

Answer

A, B

Explanation

`E_1=` Electric field due to charge q at distance a
`=(1/(4piepsilon_0))(q/a^2)`
`E_2`= Electric field due to charge at distance `sqrt2a`
`=(1/(4piepsilon_0))q/((sqrt2a)^2)=E_1/2`
`Net electric field at P,
`E_("net") =sqrt2 E_1+E_2/2` ( In the directioin of `E_2`)
`=sqrt2E_1+E_1/2`
`(sqrt2+1/2)E_1`
`((2sqrt2+1)q)/(8piepsilon_0a^2)`