JEE Main 2024 Physics question
If Rydberg's constant is R, the longest wavelength of radiation in Paschen series will be , where α = .
Answer: 144
Solution
For the Paschen series n₁ = 3, and the longest wavelength corresponds to n₂ = 4: 1/λ = R(1/9 − 1/16) = 7R/144, so λ = 144/(7R) and α = 144.