Question

The frequency of light emitted for the transition n = 4 to n = 2 of $He^+$ isequalto the transition in H atom corresponding to which of the following?

• A. n = 2 to n = 1
• B. n = 3 to n = 2
• C. n = 4 to n = 3
• D. n = 3 to n = 1

Answer 1

Answer: (A)

n = 2 to n = 1

Answer 2

$hv = \Delta E = 13.6 \,z^{2} \left(\frac{1}{n^{2}_{1}}-\frac{1}{n^{2}_{2}}\right)$ $\vee_{He+} = \vee_{H} � z^{2}\left(\frac{1}{\left(\frac{n_{1}}{2}\right)^{2}}-\frac{1}{\left(\frac{n_{2}}{2}\right)^{2}}\right)$ $= \vee_{H} \left(\frac{1}{\left(\frac{2}{2}\right)^{2}}-\frac{1}{\left(\frac{4}{2}\right)^{2}}\right)$ For H-atom $n_{1} = 1, n_{2} = 2$