Select the pair whose dimensions are the same.

$A$ 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 :-

What is the dimensional formula of the spring constant $k$?

$MLT^{-1}$ represents the dimensional formula of

The dimensions of torque are the same as that of

The $SI$ unit of a physical quantity is pascal-second. The dimensional formula of this quantity will be ..............