Question

The wavelength of limiting line of Paschen's series of H-spectra is :-

• A. $3800\mathring{A}$
• B. $820\mathring{A}$
• C. $8208\mathring{A}$
• D. $4000\mathring{A}$

Answer 1

Answer: (C)

limiting line of paschen's series $:\infty \to 3$
$\frac{1}{\lambda }=R\times Z^2\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$
$\frac{1}{\lambda }=R\times 1\left(\frac{1}{9}-\frac{1}{\infty }\right)\Rightarrow \lambda =9\times \frac{1}{R}$
$\lambda =9\times 912$
$=8208\mathring{A}$