Question

The electric field intensity at a point 2 meters from the surface of a uniformly charged conducting sphere is 1920 N/C. At a point 4 meters from its center, the electric field intensity is 3000 N/C.

a.) Determine the radius of the sphere. Determine the electric field intensity at a point:
(b.) 2m from its center,
(c.) 6m from its center, and
(d.) 4m from its surface.

Please help me.

Answer 1

outside the sphere, E=kq/r^2

E=kQ/(r+2)^2=1920
E=kQ/4^2=3000

kq=16*3000
1920=16*3000/(r+2)^2

solve for r

r = 4 sqrt (3000/1920)-2 check that math.