If an insulated non-conducting sphere of radius $R$ has a uniform charge density $\rho$,the electric field at a distance $r$ from the center of the sphere $(r < R)$ will be:

Two long thin charged rods with charge density $\lambda$ each are placed parallel to each other at a distance $d$ apart. The force per unit length exerted on one rod by the other will be (where $k = \frac{1}{4 \pi \varepsilon_0}$)

Obtain the expression for the electric field due to a straight wire of infinite length with a linear charge density $\lambda$.

As shown in the figure,a cuboid lies in a region with an electric field $\vec{E} = 2x^2 \hat{i} - 4y \hat{j} + 6 \hat{k} \; N/C$. The magnitude of the charge within the cuboid is $n \varepsilon_0 \; C$. The value of $n$ is $............$ (if the dimensions of the cuboid are $1 \times 2 \times 3 \; m^3$)

Consider a solid insulating sphere of radius $R$ with charge density varying as $\rho = \rho_0 r^2$,where $\rho_0$ is a constant and $r$ is measured from the centre. Consider two points $A$ and $B$ at distances $x$ and $y$ respectively $(x < R, y > R)$ from the centre. If the magnitudes of the electric fields at points $A$ and $B$ are equal,then:

The electric field intensity on the surface of a solid charged sphere of radius $r$ and volume charge density $\rho$ is ( $\epsilon_0=$ permittivity of free space).