In Li+ +, electron in first Bohr orbit is excited to a level by a… | JEE Main 2019 (10 Apr, Shift 2)

Q58JEE Main 2019 · 10 APR · SHIFT 2Difficult

Transitions, Photon Emission & Excitation

In Li+ +, electron in first Bohr orbit is excited to a level by a radiation of wavelength $\lambda$ . When the ion gets deexcited to the ground state in all possible ways (including intermediate emissions), a total of six spectral lines are observed. What is the value of $\lambda$ ?

(Given: H = 6.63 × 10–34 Js; c = 3 × 108 ms –1)

Show answer and solution

Answer: (a)

Six lines: $\frac{n(n-1)}{2} = 6 \Rightarrow$ excited to $n = 4$ .
For Li $^{++}$ ( $Z = 3$ ): $E = 13.6 \times 9 \times \left(1 - \frac{1}{16}\right) = 114.75$ eV
$\lambda = \frac{hc}{E} = \frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{114.75 \times 1.6 \times 10^{-19}} = 1.08 \times 10^{-8}$ m
So the answer is (a) 10.8 nm.

Report a mistake

More questions on Transitions, Photon Emission & Excitation

Radiation coming from transitions n = 2 to n = 1 of hydrogen atoms fall on He+ ions in n…JEE Main 2019 (8 Apr, Shift 1)
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

Transitions, Photon Emission & Excitation question from JEE Main 2019 (10 Apr, Shift 2)

More questions on Transitions, Photon Emission & Excitation