Compare the activation overvoltages of two hydrogen fuel cells operating at $60C,$ one with a platinum catalyst and another with a nickel catalyst. Given that the exchange current density for platinum is $5\mathrm{.}0{10}^{-4}\frac{A}{c}{m}^2$ and for nickel is $6\mathrm{.}0{10}^{-6}\frac{A}{c}{m}^2,$ calculate the activation overvoltages for both cases.