Spherical capacitor. A spherical capacitor consists of two concentric spherical conducting shells separated by a certain dielectric. One spherical shell is earthed and other is used to store charge on it.
Expression for capacitance of a spherical capacitor
Let P and Q be two spherical conducting shells of a spherical capacitor as shown in Fig. Let a and b be their respective radii. Let a charge + q be given to inner shell P, so -q charge will be induced on the inner surface of shell Q, whose outer surface is earthed.
The electric field intensity E on gaussian spherical shell (as shown by dotted lines) of radius r is given by
E = \(\frac{1}{4\piɛ_o} \frac{q}{r^2}\) .......................(1)
The potential difference between two spherical shells P and Q is given by
