Question

If electrons in hydrogen sample return from $7$th shell to $4$th shell then how many maximum number of lines can be observed in the spectrum of hydrogen?

• A. $1$
• B. $2$
• C. $5$
• D. $6$

Answer 1

Answer: (D)

$6$

$\frac{1}{\lambda }=R{z}^2(\frac{1}{n_1^2}-\frac{1}{n_2^2})$ $n_1=7$ $n_2=4$

no of spectral lines=$\frac{(n_1-n_2)(n_1-n_2+1)}{2}$

=$\frac{(7-4)(7-4+1)}{2}$

=$\frac{\left(3\right)\left(4\right)}{2}$

6 spectral lines