Radiation coming from transitions n = 2 to n = 1 of hydrogen atoms… | JEE Main 2019 (8 Apr, Shift 1)

Q59JEE Main 2019 · 8 APR · SHIFT 1Difficult

Transitions, Photon Emission & Excitation

Radiation coming from transitions n = 2 to n = 1 of hydrogen atoms fall on He+ ions in n = 1 and n = 2 states. The possible transition of helium ions as they absorb energy from the radiation is:

Show answer and solution

Answer: (c)

Photon from H ( $2 \to 1$ ): $E = 13.6\left(1 - \frac{1}{4}\right) = 10.2\text{ eV}$ .
He $^+$ levels: $E_n = -\frac{54.4}{n^2}$ eV, so $E_1 = -54.4$ , $E_2 = -13.6$ , $E_3 = -6.04$ , $E_4 = -3.4$ , $E_5 = -2.18$ eV.
From $n = 2$ : $E_4 - E_2 = -3.4 + 13.6 = 10.2\text{ eV}$ , an exact match.
No other listed jump needs exactly $10.2$ eV.
So the answer is (c) $n = 2 \rightarrow n = 4$ .

Report a mistake

More questions on Transitions, Photon Emission & Excitation

If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a…NEET 2016 (Phase 2)
A hydrogen atom makes a transition from n = 2 to n = 1 and emits a photon. This photon…JEE Main 2016 (9 Apr, Shift 1)
Hydrogen (₁H¹), Deuterium (₁H²), singly ionised Helium (₂He⁴)⁺ and doubly ionised lithium…JEE Main 2014
Hydrogen atom in ground state is excited by a monochromatic radiation of λ = 975 Å…NEET 2014 (AIPMT)
The radiation corresponding to 3 → 2 transition of hydrogen atom falls on a metal surface…JEE Main 2014
A 12.5 eV electron beam is used to bombard gaseous hydrogen at room temperature. It will…JEE Main 2013 (25 Apr, Shift 1)
In a hydrogen like atom electron make transition from an energy level with quantum number…JEE Main 2013
Hydrogen atom is excited from ground state to another state with principal quantum number…JEE Main 2012 (AIEEE)

Transitions, Photon Emission & Excitation question from JEE Main 2019 (8 Apr, Shift 1)

More questions on Transitions, Photon Emission & Excitation