Atoms Ques 28
28. An electron changes its position from orbit $n=2$ to the orbit $n=4$ of an atom. The wavelength of the emitted radiations is $(R=$ Rydberg’s constant)
[2001]
(a) $\frac{16}{R}$
(b) $\frac{16}{3 R}$
(c) $\frac{16}{5 R}$
(d) $\frac{16}{7 R}$
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Answer:
Correct Answer: 28.(b)
Solution:
- (b) $\bar{{}v}=R(\frac{1}{n_1^{2}}-\frac{1}{n_2^{2}})$, where $n_1=2, n_2=4$
$\bar{{}v}=R(\frac{1}{4}-\frac{1}{16})$
$\frac{1}{\lambda}=R(\frac{12}{4 \times 16}) \quad \Rightarrow \quad \lambda=\frac{16}{3 R}$
BETA
