Chapter 31 - Atomic Physics - Problems and Conceptual Exercises - Page 1115: 93

(a) $n=12$ (b) $7.62nm$

(a) We know that $n=\frac{\lambda_n}{2\pi r_1}$ We plug in the known values to obtain: $n=\frac{3.99\times 10^{-9}}{(2)(3.14)(5.29\times 10^{-11})}$ $n=12$ (b) The Bohr radius is given as $r_n=n^2\times r_1$ We plug in the known values to obtain: $v_n=(12^2)(5.29\times 10^{-11}m)$ $v_n=7.62nm$