The adjacent diagram shows a charge $+Q$ held on an insulating support $S$ and enclosed by a hollow spherical conductor. $O$ represents the centre of the spherical conductor. and $P$ is a point such that $OP = x $ and $SP = r$ . The electric field at point $P$ will be
$\frac{Q}{{4\pi { \in _0}{x}}}$
$\frac{Q}{{4\pi { \in _0}{r^2}}}$
$0$
None of the above
Can a metal be used as a medium for dielectric
Two spheres of radius $R$ and $2R$ having charge $Q$ and $2Q$ respectively are placed far away from each other. How much charge will flow when key $'k'$ is pressed ?
A hollow metal sphere of radius $5\,\, cm$ is charged so that the potential on its surface is $10\,\, V$. The potential at the centre of the sphere is.....$V$
Two isolated metallic solid spheres of radii $R$ and $2 R$ are charged such that both have same charge density $\sigma$. The spheres are then connected by a thin conducting wire. If the new charge density of the bigger sphere is $\sigma^{\prime}$. The ratio $\frac{\sigma^{\prime}}{\sigma}$ is
As shown in the figure, a point charge $Q$ is placed at the centre of conducting spherical shell of inner radius a and outer radius $b$. The electric field due to charge $Q$ in three different regions I, II and III is given by: $( I : r < a , II : a < r < b , III : r > b )$