A thin spherical conducting shell of radius $R$ has charge $q$. Another charge $Q$ is placed at the centre of the shell. The electrostatic potential at a point $P$ at a distance $R/2$ from the centre of the shell is
$\frac{{2Q}}{{4\pi {\varepsilon _0}R}}$
$\frac{{{{(q + Q)}^2}}}{{4\pi {\varepsilon _0}R}}$
$\frac{{2Q}}{{4\pi {\varepsilon _0}R}} - \frac{{2q}}{{4\pi {\varepsilon _0}R}}$
$\frac{{2Q}}{{4\pi {\varepsilon _0}R}} + \frac{{q}}{{4\pi {\varepsilon _0}R}}$
A hollow cylinder has charge $q$ $C$ within it. If $\phi $ is the electric flux in unit of voltmeter associated with the curved surface $B$, the flux linked with the plane surface $A$ in unit of voltmeter will be
A point charge $+Q$ is positioned at the centren of the base of a square pyramid as shown. The flux through one of the four identical upper faces of the pyramid is
An electric dipole is situated in an electric field of uniform intensity $E$ whose dipole moment is $p$ and moment of inertia is $I$. If the dipole is displaced slightly from the equilibrium position, then the angular frequency of its oscillations is
Side length of equilateral triangle is $d. P$ is mid of side then potential at point $P, V_P$ is
Four point $+ve$ charges of same magnitude $(Q)$ are placed at four corners of a rigid square frame in $xy$ plane as shown in figure. The plane of the frame is perpendicular to $z-$ axis. If a $-ve$ point charges is placed at a distance $z$ away from the above frame $(z << L)$ then