L}^{-3}}],\ [a]=[L]\] and \[[T]=[M{{T}^{-2}}]\] Comparing both sides, we get\[a=\frac{1}{2},\,b=\frac{3}{2}\] and \[c=\frac{-1}{2}\] \ \[\eta =\frac{k{{\rho }^{1/2}}{{a}^{3/2}}}{\SQRT{T}}\]