Two isolated metallic spheres of radii $2 \,cm$ and $4 \,cm$ are given equal charge,then the ratio of charge density on the surfaces of the spheres will be

$A$ uniformly charged conducting sphere of $2.4 \, m$ diameter has a surface charge density of $80.0 \, \mu C m^{-2}$. The charge on the sphere is nearly

$A$ spherical conducting shell of inner radius $r_1$ and outer radius $r_2$ has a net charge $Q$. $A$ point charge $-q$ is placed at the center of the shell. Determine the surface charge density on the inner and outer surfaces of the shell.

Charges $Q, 2Q$ and $-Q$ are given to three concentric conducting shells $A, B$ and $C$ respectively as shown. The ratio of charges on the inner and outer surfaces of shell $C$ will be:

$A$ square plate of side $a$ is placed in the $xy$-plane with its center at the origin. If the surface charge density of the square plate is given by $\sigma = xy$,then the total charge on the plate will be:

Explain linear charge density,surface charge density,and volume charge density for uniform charge distribution.