Question

Find the longest wavelength present in the radiation emitted when hydrogen atoms excited to n = 3 states return to their ground state.

• A. 103 nm
• B. 122 nm
• C. 656 nm
• D. 912 nm

Answer 1

Answer: (C)

656 nm

Answer 2

l_max Ž E_min (3 ® 2)

$\frac{1}{\lambda_{\max}}$ = R (1)²$\left( \frac{1}{2^{2}} - \frac{1}{3^{2}} \right)$ Ž $\frac{1}{\lambda_{\max}}$= R$\left( \frac{5}{36} \right)$

l_max =$\frac{36}{5R}$= $\frac{36}{5}$× 912 Å = 6560Å = 656 nm