A solid conducting sphere of radius $a$ has a net positive charge $2Q$. A conducting spherical shell of inner radius $b$ and outer radius $c$ is concentric with the solid sphere and has a net charge $-Q$. The surface charge density on the inner and outer surfaces of the spherical shell will be
$ - \frac{{2Q}}{{4\pi {b^2}}},\frac{Q}{{4\pi {c^2}}}$
$ - \frac{Q}{{4\pi {b^2}}},\frac{Q}{{4\pi {c^2}}}$
$0,\frac{Q}{{4\pi {c^2}}}$
None of the above
A spherical conducting shell of inner radius $r_1$ and outer radius $r_2$ has a charge $Q. $
$(a)$ A charge $q$ is placed at the centre of the shell. What is the surface charge density on the inner and outer surfaces of the shell?
$(b)$ Is the electric field inside a cavity (with no charge) zero, even if the shell is not spherical, but has any irregular shape? Explain.
‘At the surface of a charged conductor electrostatic field must be normal to the surface at every point’. Explain.
The electric field near a conducting surface having a uniform surface charge density $\sigma $ is given by
Two conducting spheres of radii $5\, cm$ and $10\, cm$ are given a charge of $15\,\mu C$ each. After the two spheres are joined by a conducting wire, the charge on the smaller sphere is.......$\mu C$
An empty thick conducting shell of inner radius $a$ and outer radius $b$ is shown in figure.If it is observed that the inner face of the shell carries a uniform charge density $-\sigma$ and the surface carries a uniform charge density $ '\sigma '$
If the outer surface of the shell is earthed, then identify the correct statement(s)