A spherical conductor of radius 12 cm has a charge of 1.6 × 10–7C distributed uniformly on its surface. What is the electric field
(a) inside the sphere
(b) just outside the sphere
(c) at a point 18 cm from the centre of the sphere?
Given, q = 1.6 x 10-7 C
Radius of the sphere, r = 12 cm = 0.12 m
(a) Inside the sphere: The charge on a conductor resides on its outer surface. Therefore, electric field inside the sphere is zero.
(b) Just outside the sphere: For a point on the charged spherical conductor or outside it, the charge may be assumed to be concentrated at its center.
Therefore, the electric field just outside the sphere is given as:
where, q is the charge due to which the field is being calculated
putting the values of “r” and “q” in the equation, we get,
∴E = 105 N/C
(c) At a point 18 cm from the center: Given, R = 18 cm
Electric field at a point 18 cm from the center
∴ E = 4.4 x 104 N/C