GATE PH Atomic and Molecular Physics PYQs & Answers

Questions 1–10 of 44. Imported answers require independent review unless marked reviewed.

Raman spectrum of a molecule was recorded using a source of wavelength 500 Å. The first Stokes line is observed at 510 Å. The first anti-Stokes line will appear at a wavelength

(in Å). The value of

(rounded off to nearest integer) is ____

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An atom has two energy levels with energy difference 2.2 eV between them. A gas of these atoms is with

atoms in the upper state and

atoms in the lower state. Ignoring spontaneous emission, the maximum possible energy released by gas of atoms by stimulated emission is

Joules. The value of

(rounded off to one decimal place) is ____ (

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Rotational spectrum of a diatomic molecule consists of lines of equal spacing with an interval of 20 cm

. Its moment of inertia is found to be

kg m

, the value of

(rounded off to one decimal place) is _____

(

J.s, speed of light in vacuum

m.s

)

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Potential energy of two diatomic molecules P and Q of the same reduced mass is shown in the figure. According to this diagram, which of the following option(s) is/are correct?

Your answerSelect all correct options. You can choose more than one.

The equilibrium inter-nuclear distance of Q is more than that of P

The total energy

separates bound and unbound states of the molecules

The lowest vibrational frequency of P is larger than that of Q

Dissociation energy of Q is more than that of P

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The effective magnetic moment (in units of Bohr magneton) for the ground state of an isolated

ion with 6 unpaired electrons in the

shell according to Hund’s rules is (in integer) _____

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The screened nuclear charge of neutral Helium atom is given as

, where

is the magnitude of the electronic charge. Assuming the Bohr model of the atom for which the energy levels are

atomic units (

is the atomic number), the first ionization potential of Helium in atomic units is

Your answerChoose one option.

0.89

1.78

0.94

3.16

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The mean distance between the two atoms of HD molecule is

, where H and D denote hydrogen and deuterium, respectively. The mass of the hydrogen atom is

. The energy difference between two lowest lying rotational states of HD in multiples of

Your answerChoose one option.

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Atomic numbers of V, Cr, Fe and Zn are 23, 24, 26 and 30, respectively. Which one of the following materials does NOT show an electron spin resonance (ESR) spectra?

Your answerChoose one option.

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The spin-orbit interaction in a hydrogen-like atom is given by the Hamiltonian

where

is a real constant. The splitting between levels

and

due to this interaction is

Your answerChoose one option.

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An atom is subjected to a weak uniform magnetic field

. The number of lines in its Zeeman spectrum for transition from

Your answerChoose one option.

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GATE PH Atomic and Molecular Physics PYQs

How to practice Atomic and Molecular Physics

Question 34

Question 58

Question 62

Question 28

Question 32

Question 36

Question 15

Question 21

Question 37

Question 42