Question

Find out the wavenumber, when an electron jumps from 2^nd orbit to 1^st.

(a) 82357.75 cm^-1

(b) 105,677 cm^-1

(c) 82257.75 cm^-1

(d) 109,677 cm^-1

This question was addressed to me in a job interview.

This key question is from Developments Leading to the Bohr’s Model of Atom topic in section Structure of Atom of Chemistry – Class 11

Answer 1

Correct choice is (c) 82257.75 cm^-1

The best I can explain: The Swedish spectroscopist, Johannes Rydberg gave a formula; Wavenumber = RH[(1/n1)^2-(1/n2)^2]. Here RH is the Rydberg constant and is equal to 109,677 cm^-1. Wavenumber = 109,677(3/4) = 82257.75 cm^-1.