dimension of $L=\frac{M L T^{-2}}{Q^{2}} \cdot T^{2}=M L T^{0} Q^{-2}$
$E = i ^{2} R T \Rightarrow R =\frac{ E }{ i ^{2} t }$
dimension of $R =\frac{ M L T ^{-2}}{ Q ^{2}} \cdot T ^{-1}= M L T ^{-1} Q ^{-2}$
$\left(\frac{L}{R}\right)=\frac{M L T^{0} Q^{-2}}{M L T^{-1} Q^{-2}}=[T]$