Question

If n = 2 for $He^+$ ion than find out the wave length

• A. 3.32 $\mathring{A}$
• B. 6.42 $\mathring{A}$
• C. 1.47 $\mathring{A}$
• D. 2.37 $\mathring{A}$

Answer 1

Answer: (A)

$2\pi r=n\lambda$
$2\pi\times0.529\times\frac{n^{2}}{Z}=n\lambda$
$\lambda=\frac{2\pi\times0.529\times n^{2}}{n\times Z}$
$\lambda=\frac{2\times3.14\times0.529\times2^{2}}{2\times2}$
$\lambda=3.33\mathring{A}$