JEE Main 2024PhysicsAtomic PhysicsEasyNumerical

JEE Main 2024 — Atomic Physics Question with Solution

JEE Main 2024 (27 Jan Shift 2)

Question

If Rydberg's constant is R, the longest wavelength of radiation in Paschen series will be α7R, where α=______.

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Show full solutionCorrect answer: 144
Correct answer
144

Step-by-step explanation

In the Paschen radiation series, the longest wavelength corresponds to the transition between n=3 and n=4.

The formula for the wavelength in the given transition can be written as, 

1λ=RZ21n12-1n22   ...1

From equation (1), it follows that

1λ=RZ2132-142=RZ219-116=7RZ29×16⇒λ=1447R

 Hence, α=144.

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About this question

This is a previous-year question from JEE Main 2024, covering the Atomic Physics chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.