Atoms And Nuclei Question 44
Question: In terms of Rydberg’s constant R, the wave number of the first Balmer line is [MP PMT 1996]
Options:
A) R
B) 3R
C) $ \frac{5R}{36} $
D) $ \frac{8R}{9} $
Show Answer
Answer:
Correct Answer: C
Solution:
Wave number $ =\frac{1}{\lambda }=R( \frac{1}{n_{1}^{2}}-\frac{1}{n_{2}^{2}} ) $ For first Balmer line n1= 2, n2=3
$ \therefore $ Wave number $ =R( \frac{1}{2^{2}}-\frac{1}{3^{2}} )=R( \frac{9-4}{9\times 4} )=\frac{5R}{36} $
