Question

A sphere of radius `0.03m` is suspended within a hollow sphere of radius `0.05m`. If the inner sphere is charged to a potential of `1500` volt and outer sphere is earthed. Find the capacitance and the charge of the inner sphere.

Answer 1

Correct Answer - `8.33 pF, 1.25xx10^(-8) C`
`a = 0.03 m, b = 0.05 m, V = 1500 V`
Capacitance of spherical capacitor is
`C = (4 pi in_(0) ab)/(b - a) = (0.03xx0.05)/(9xx10^(9) (0.05 - 0.03)) = 8.33 pF`
`q = CV = 8.33xx10^(-12) xx1500 = 1.25xx10^(8) C`