Write the dimensional formula for energy density.

The electrical resistance $R$ of a conductor of length $l$ and area of cross-section $a$ is given by $R = \frac{\rho l}{a}$,where $\rho$ is the electrical resistivity. What is the dimensional formula for electrical conductivity $\sigma$,which is the reciprocal of resistivity?

The dimension of $P = \frac{B^2 l^2}{m}$ is,where $B = \text{magnetic field}$,$l = \text{length}$,$m = \text{mass}$.

If $\varepsilon_0$ is the permittivity of free space and $E$ is the electric field,then $\varepsilon_0 E^2$ has the dimensions

The dimensional formula of capacitance is . . . . . . . Take $Q$ as the dimensional formula of charge.

Match the following two columns:

Column-$I$	Column-$II$
$(A)$ Electrical resistance	$(p)$ $M L^3 T^{-3} A^{-2}$
$(B)$ Electrical potential	$(q)$ $M L^2 T^{-3} A^{-2}$
$(C)$ Specific resistance	$(r)$ $M L^2 T^{-3} A^{-1}$
$(D)$ Specific conductance	$(s)$ None of these