Question

The wave number of energy emitted when electron jumps from fourth orbit to second orbit in hydrogen in 20497 $c{m}^{-1}$. The wave number of energy for the same transition in $H{e}^{+}$ is

• A. $5,099c{m}^{-1}$
• B. $20,497c{m}^{-1}$
• C. $40,994c{m}^{-1}$
• D. $81,988c{m}^{-1}$

Answer 1

The correct option is D $81,988c{m}^{-1}$

$\overrightarrow{\nu }\propto z^2$
$\frac{{\overrightarrow{\nu }}_2}{{\overrightarrow{\nu }}_1}={\left[\frac{z_2}{z_1}\right]}^2={\left[\frac{2}{1}\right]}^2=\frac{4}{1}$
${\overrightarrow{\nu }}_2=4{\overrightarrow{\nu }}_1=4\times 20497=81988c{m}^{-1}$