Question

The first emission line in the atomic spectrum of hydrogen in the Balmer series appears at:

• A. \(\dfrac{9R}{400}\,\text{cm}^{-1}\)
• B. \(\dfrac{7R}{144}\,\text{cm}^{-1}\)
• C. \(\dfrac{3R}{4}\,\text{cm}^{-1}\)
• D. (5R)/(36)cm⁻1

Hint:

Balmer series involves transitions ending at n=2.

Answer 1

The Correct Option is D

Step 1: First Balmer line corresponds to transition n=3 → 2.
Step 2: Rydberg formula: ν=R((1)/(2²)-(1)/(3²)) =R((1)/(4)-(1)/(9))=(5R)/(36)