JEE Main 2017ChemistryStructure of AtomMediumMCQ

JEE Main 2017 — Structure of Atom Question with Solution

JEE Main 2017 (08 Apr Online)

Question

If the shortest wavelength in Lyman series of hydrogen atom is A, then the longest wavelength in Paschen series of He+ is

Choose an option

Show full solutionCorrect option: B
Correct answer
B36A7

Step-by-step explanation

1λ=RH×(Z)2 1n12−1n22

Shortest wavelength for Lyman series of H atom

n1=1 (Lyman series)

n2=∞

SO, 1λ1=1×RH11−1∞

λ1=1RH=A   ∴λ=A

longest wavelength for Paschen series of He+ atom

n1=3

n2=4

1λ2=(2)2×RH 1(3)2−1(4)2

1λ2=4×RH 79×16=R×736

λ2=367RH=367A.
 

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About this question

This is a previous-year question from JEE Main 2017, covering the Structure of Atom chapter of Chemistry. 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.