Two semicircular rings lying in the same plane of uniform linear charge density $\lambda$, have radii $r$and $2r.$They are joined using two straight uniformly charged wires of linear charge density $\lambda$and length $r$as shown in the figure. The magnitude of the electric field at the common centre of semicircular rings is

Two concentric rings, one of radius $R$and total charge $+Q$and the second of radius $2R$and total charge $-\sqrt{8}Q,$lie in the $xy$plane ($z=0$plane). The common center of rings lies at origin and the common axis coincides with the $z$ axis. The charge is uniformly distributed on both rings. At what distance from the origin is the net electric field on the $z$-axis zero?

An infinitely long wire is kept along $z$-axis from $z=-\infty$to $z=+\infty ,$having uniform linear charge density $\frac{10}{9} \mathrm{nC}/\mathrm{m}.$The electric field at the point $(6 \mathrm{cm},8 \mathrm{cm},10 \mathrm{cm})$will be

Two point charges $q_A$ and $q_B$ are placed at some separation on positive $x$-axis at points $\left(x_A, 0\right)$ and $\left(x_B, 0\right)$. It is given that $\left|q_A\right|>\left|q_B\right|$ and $x_B>x_A$. If the null point is the point where the net electric field due to both the charges is zero, then

Figure shows the electric field lines around three point charges $A$, $B$ and $C$.

Which charges are positive?

Figure shows the electric field lines around three point charges $A$, $B$ and $C$.

Which charge has the largest magnitude? Why?

Figure shows the electric field lines around three point charges $A$, $B$ and $C$.

Five charges, $q$ each are placed at the corners of a regular pentagon of side $a$.

What will be the electric field at $O$, the center of the pentagon?

Five charges, $q$ each are placed at the corners of a regular pentagon of side $a$.

What will be the electric field at $O$ if the charge from one of the corners (say $A$) is removed?