‘The interior of a conductor can have no excess charge in the static situation’. Explain.
A neutral conductor has equal amounts of positive and negative charges in every small volume or surface element.
When the conductor is charged the excess charge can reside only on the surface in the static situation.
Let us consider a Gaussian surface inside the conductor and close to the surface.
At all points inside the conductor $\overrightarrow{\mathrm{E}}=0$ hence from $\phi_{\mathrm{E}}=\int \overrightarrow{\mathrm{E}} \cdot d \overrightarrow{\mathrm{S}}, \phi_{\mathrm{E}}=0$
According to Gauss's law,
$\phi_{\mathrm{E}}=\frac{q}{\epsilon_{0}}, \phi_{\mathrm{E}}=0$
$\therefore q=0$
Hence, there is no net charge at any point inside the conductor and any excess charge must reside at the surface.
Two concentric hollow conducting spheres of radius $r$ and $R$ are shown. The charge on outer shell is $Q$. What charge should be given to inner sphere so that the potential at any point $P$ outside the outer sphere is zero?
Four metal conductors having different shapes
$1.$ A sphere $2.$ Cylindrical
$3.$ Pear $4.$ Lightning conductor
are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is
Three concentric conducting spherical shells have radius $ r, 2r$ and $3r$ and $Q_1, Q_2$ and $Q_3$ are final charges respectively. Innermost and outermost shells are already earthed as shown in figure. Choose the wrong statement.
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.......$\mu C$
A point charge $q$ is placed in a cavity in a metal block. If a charge $Q$ is brought outside the metal, then the electric force experienced by $q$ is