$A$ conducting sphere of radius $R = 20 \ cm$ is given a charge $Q = 16 \ \mu C$. What is the electric field $\overrightarrow{E}$ at the centre?

$A$ conducting sphere of radius $0.1 \ m$ has a uniform charge density $1.8 \ \mu C/m^2$ on its surface. The electric field in free space at a radial distance of $0.2 \ m$ from the center of the sphere is $(\varepsilon_0 = \text{permittivity of free space})$

$A$ hollow sphere of charge does not produce an electric field at any

An infinite non-conducting sheet has a surface charge density $2 \times 10^{-7} \text{ C/m}^2$ on one side. The distance between two equipotential surfaces whose potential difference is $90 \text{ V}$ is (assume $\frac{1}{4 \pi \varepsilon_0} = 9 \times 10^9 \text{ Nm}^2/\text{C}^2$):

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

The electric field in a region is radially outward with magnitude $E = A r_0$. The charge contained in a sphere of radius $r_0$ centered at the origin is