A quantity X is given by $\varepsilon_0 L \frac{\Delta V}{\Delta t}$ where ε₀ is the permittivity of the free space, L is a length, ΔV is a potential difference and Δt is a time interval. The dimensional formula for X is the same as that of

current

Using the relations $E=\frac{\sigma}{\varepsilon_o}$ and $\Delta V=E . L$, we get

$X=\frac{\sigma}{E} \cdot L \cdot \frac{E L}{\Delta t}=\frac{q}{L^2} \frac{L^2}{\Delta t}=\frac{q}{\Delta t}$

∴ (d)