Question

A metallic spherical shell has an inner radius r1 and outer r2. A charge Q is placed at the center of the shell. the ratio of surface change density on the inner surface to outer surface of the shell is

Answer 1

When a charge +q is placed at the centre of spherical cavity

Charge included o the inner surface of shell

= -q......(1)

Charge induced on the outer surface of shell

= +q.......(1)

∴ Surface charge density on the inner

Surface = $\large\rm { \frac {+q}{4πR \frac {2}{2}}}$