Question

obtain an expression for electric field intensity at a point outside a charged conducting sphere

Answer 1

let the distance body point p form the centre 0 is ×
then imagine a sphere whose radius is ×and centre is 0
the point p is enclosed by a small surface ds
If the intensity at p is E (vector)
then flux let linked with the small surface
d

Answer 2

on conduction body all charges lies on the surface