Point charge q s placed at a point on the axis of a square non-conducting surface. The axis is perpendicular to the square surface and is passing through its centre. Flux of electric field throught he square caused due to charged q is ϕ. If the square is given a surface change of uniform density σ, find the force on the square surface due to point charge q.
![](https://sahay.guru/wp-content/uploads/2020/10/38-1-22-1024x482.jpg)
![](https://sahay.guru/wp-content/uploads/2020/10/37-2-21-1024x684.jpg)