If two infinite plane sheets having same surface charge density $\sigma$ are placed parallel to each other,then the electric field between the two sheets is . . . . . . .

$A$ cube is placed inside an electric field,$\overrightarrow{E} = 150 y^2 \hat{j}$. The side of the cube is $0.5 \, m$ and it is placed in the field as shown in the figure. The charge inside the cube is $..... \times 10^{-11} \, C$.

If the uniform surface charge density on an infinite plane sheet is $\sigma$,the electric field near the surface will be . . . . . . .

The electric field at a distance of $20 \ cm$ from the center of a charged spherical shell of radius $10 \ cm$ is $100 \ V/m$. What is the electric field at a distance of $3 \ cm$ from the center?

An electron is moving under the influence of the electric field of a uniformly charged infinite plane sheet $S$ having surface charge density $+\sigma$. The electron at $t=0$ is at a distance of $1 \,m$ from $S$ and has a speed of $1 \,m/s$. The maximum value of $\sigma$ if the electron strikes $S$ at $t=1 \,s$ is $\alpha \left[ \frac{m \epsilon_0}{e} \right] \,C/m^2$. The value of $\alpha$ is:

Two infinitely long parallel wires having linear charge densities $\lambda_1$ and $\lambda_2$ respectively are placed at a distance of $R$ meters. The force per unit length on either wire will be $(K = \frac{1}{4\pi\varepsilon_0})$.