The dimension of $\frac{1}{{\sqrt {{\varepsilon _0}{\mu _0}} }}$ is that of

Dimensions of magnetic field intensity are:

Which of the following pairs of physical quantities has the same dimensions?

$A$ dimensionless quantity

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 dimensional formula of polarization $P$ is . . . . . . .