Question

In which of the following transition will the wavelength be minimum?

• A. $n=6$ to $n=4$
• B. $n=4$ to $n=2$
• C. $n=3$ to $n=1$
• D. $n=2$ to $n=1$

Answer 1

Answer: (C)

$n=3$ to $n=1$

The wavelength of photon given is ;

$\frac{1}{\lambda }=R(\frac{1}{n_f^2}-\frac{1}{n_i^2})$

$\Rightarrow$ For minimum $\lambda ,\frac{1}{n_f^2}-\frac{1}{n_i^2}$ should be maximum

(i) $\frac{1}{4^2}-\frac{1}{6^2}=0.034$

(ii) $\frac{1}{2^2}-\frac{1}{4^2}=0.187$

(iii) $\frac{1}{1^2}-\frac{1}{3^2}=0.888$ This is maximum so corresponding wavelength will be minimum

(iv) $\frac{1}{1^2}-\frac{1}{2^2}=0.75$.

Therefore, the option is C.