a
\(V\) = Rate of flow \(=\frac{{{\rm{Volume }}}}{{{\rm{sec}}}} = [{L^3}{T^{ - 1}}]\),

\(P\) = Pressure = \([M{L^{ - 1}}{T^{ - 2}}]\),

\(r\) = Radius = \([L]\)

\(\eta \) = Coefficient of viscosity = \([M{L^{ - 1}}{T^{ - 1}}]\),

\( l\) = Length = \( [L]\)

\(V = \frac{{\pi P\,{r^4}}}{{8\eta l}}\)

\(\therefore [{L^3}{T^{ - 1}}] = \frac{{[M{L^{ - 1}}{T^{ - 2}}]\,[{L^4}]}}{{[M{L^{ - 1}}{T^{ - 1}}]\,[L]}}\) = \([{L^3}{T^{ - 1}}]\)

\(L.H.S. = R.H.S.\)