Question

A spherical shell of radius $R$ has a change $+q$ units. The electric field due to the shell at a point

• A. Inside is zero and varies as $r^{-1}$ outside it
• B. Inside is constant and varies as $r^{-2}$ outside it
• C. Inside is zero and varies as $r^{-2}$ outside it
• D. Inside is constant and varies as $r^{-1}$ outside it

Answer 1

The correct option is C Inside is zero and varies as $r^{-2}$ outside it

The electric field due to a spherical shell having a charge +q+q units and radius RR at a distance rr from the centre is given by
(i) Einside=0Einside=0 (for r<Rr<R)
(ii) Esurface=q4πε0R2Esurface=q4πε0R2 (For r=Rr=R)
(iii) Eoutside=q4πε0r2Eoutside=q4πε0r2 (For r>Rr>R)
the variation of EE with rr for a spherical shell is shown in the figure