The dimension of $\frac{B^{2}}{2 \mu_{0}}$,where $B$ is magnetic field and $\mu_{0}$ is the magnetic permeability of vacuum,is

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

The dimensional formula of potential difference is ........

$A$ temperature difference can generate $e.m.f.$ in some materials. Let $S$ be the $e.m.f.$ produced per unit temperature difference between the ends of a wire,$\sigma$ the electrical conductivity and $\kappa$ the thermal conductivity of the material of the wire. Taking $\text{M, L, T, I}$ and $K$ as dimensions of mass,length,time,current and temperature,respectively,the dimensional formula of the quantity $Z=\frac{S^2 \sigma}{\kappa}$ is :-

Write the $CGS$ and $MKS$ units of the universal gravitational constant $G$. Also,write the dimensional formula of $G$.

Which one of the following is not correct?