1)

The wave number of  first emission line in the Balmer series of H- spectrum is (R= Rydberg constant)


A) $\frac{5}{36}R$

B) $\frac{9}{400}R$

C) $\frac{7}{6}R$

D) $\frac{3}{4}R$

Answer:

Option A

Explanation:

$\overline{v}= RZ^{2}\left( \frac{1}{2^{2}}-\frac{1}{3^{2}}\right)$

 $= R\left( \frac{1}{4}-\frac{1}{9}\right)=\frac{5R}{36}$