Here,                     n = 1                      h = 6.63 × 10^-34 J s             m = mass of proton = 9.11 × 10^-31 kg

                                e is charge of electron = 1.67 × 10^-19 C     k = Coulomb law constant = 9 × 10⁹ N m/C²

Hence put the values in the formula,