Calculate potential on the axis of a ring due to charge $Q$ uniformly distributed along the ring of radius $R$.
Suppose, $+Q$ charge uniformly distributed on the ring of radius $R=a$
Let us take point P to be at a distance $x$ from the centre of the ring. The charge $d q$ is at a distance $r$ from the point P then,
$r=\sqrt{x^{2}+a^{2}}$
and potential at $\mathrm{P}$ due to $d q \mathrm{~V}=\frac{k d q}{r}$
Potential at P due to charge on the whole ring,
$\mathrm{V}=k \int \frac{d q}{r}=k \int \frac{d q}{\sqrt{x^{2}+a^{2}}}$
$\mathrm{~V}=\frac{k}{\sqrt{x^{2}+a^{2}}} \int d q=\frac{k \mathrm{Q}}{\sqrt{x^{2}+a^{2}}}\left[\because \int d q=\mathrm{Q}\right]$
$\therefore$ The net electric potential,
$\mathrm{V}=\frac{\mathrm{Q}}{4 \pi \in_{0} \sqrt{x^{2}+a^{2}}}$
An electric charge $10^{-8}\ C$ is placed at the point $ (4\,m, 7\,m, 2\,m)$. At the point $(1\,m, 3\,m, 2\,m)$, the electric
Consider the points lying on a straight line joining two fixed opposite charges. Between the charges there is
Three concentric metallic spherical shell $A, B$ and $C$ or radii $a, b$ and $c$ $(a < b < c)$ have surface charge densities $- \sigma , + \sigma ,$ and $- \sigma $ respectively. The potential of shell $A$ is :
An infinitely long thin wire, having a uniform charge density per unit length of $5 nC / m$, is passing through a spherical shell of radius $1 m$, as shown in the figure. A $10 nC$ charge is distributed uniformly over the spherical shell. If the configuration of the charges remains static, the magnitude of the potential difference between points $P$ and $R$, in Volt, is. . . .
[Given: In SI units $\frac{1}{4 \pi \epsilon_0}=9 \times 10^9, \ln 2=0.7$. Ignore the area pierced by the wire.]
Charges are placed on the vertices of a square as shown. Let $E$ be the electric field and $V$ the potential at the centre. If the charges on $A$ and $B$ are interchanged with those on $D$ and $C$ respectively, then