n_{2} = n_{1} ρ + m λ_{0} = 1, 000277 \times 1 + 20 \times 5, 46 \cdot 10^{- 7} = 1, 000288

${n_2=n_1 \rho +m \lambda_0=1,000277 \times 1+20\times 5,46 \cdot 10^{-7}=1,000288}$