Two point charges `q` and `-q` are separated by a distance `2l`. Find the flux strength vector across the circle of radius R placed with its centre coinciding with the of line joining the two charges in the perpendicular plane.

Answer

A, B

Explanation

We have

`phi=(q(1-costheta))/(2epsilon_0)`
Here, flux due to `+1q` and `-q` are in same direction.
`:. phi_("total")=2pi=(q(1-costheta))/epsilon_0`
`=q/epsilon_0[1-l/(sqrt(R^2+l^2))]`
`C=(a,0,0)`