Atomic and Molecular Physics MCQs with Answers 2027

Q41

The separation between the first stokes and corresponding anti-stokes Iines of the rotational Raman spectrum in terms of the rotational constant B

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Q42

Open question

A vibrational-electronic spectrum of homonuclear binary molecules, involving electronic ground state ε'' and excited ε', exhibits a continuum at

v

cm^-1. If the total energy of the dissociated atoms in the excited state exceeds the total energy of the dissociated atoms in the ground state by E_ex cm^-1, then dissociation energy of the molecule in the ground state is

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Q43

Open question

For a multi-electron atom

l

, L and S specify the one electron orbital angular momentum, total orbital angular momentum and total spin angular momentum respectively. The selection rules for electric dipole transition between the two electronic energy levels, specified by

l

, L and S are

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Q44

Open question

Two states of an atom have definite parities. An electric dipole transition between these states is

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Q45

Open question

A collection of N atoms is exposed to a strong resonant electromagnetic radiation with N_g atoms in the ground state and N atoms in the excited state, such that N_g + N_e = N. This collection of two-level atoms will have the following population distribution

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Q46

Open question

The last two terms of the electronic configuration of manganese (Mn) atom is 3d⁵ 4s². The term factor of Mn⁴⁺ ion is

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Q47

Open question

Deuteron in its ground state has a total angular momentum J = 1 and a positive parity. The corresponding orbital angular momentum L and spin angular momentum S combinations are

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Q48

Open question

Two monochromatic waves having frequencies

ω

and

ω + Δ ω (Δ ω ≪ ω)

and corresponding wavelengths

λ

and

λ - Δ λ (Δ λ ≪ λ)

of same polarization, travelling along X-axis are superimposed on each other. The phase velocity and group velocity of the resultant wave are respectively given by

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Q49

Open question

A pure rotational Raman spectrum of a linear diatomic molecule is recorded using electromagnetic radiation of frequency

ν_{e}

. The frequency of two consecutive Stokes lines are

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Q50

Open question

The rotational partition function for a diatomic molecule of moment of inertia

I

at a temperature T is given by

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Q51

Open question

Match the typical spectra of stable molecules with the corresponding wave number range

P. Electronic spectra	1. 10⁶ cm^-1 and above
Q. Rotational spectra	2. 10⁵ - 10⁶ cm^-1
R. Molecular dissociation	3. 10⁰ - 10² cm^-1

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Q52

Open question

The molecular spectra of two linear molecules O-C-O and O-C-S are recorded in the microwave region. Which one of the following statements is correct?

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Q53

Open question

If the equation of state for a gas with internal energy U is pV =

\frac{1}{3}

U, then the equation for an adiabatic process is

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Q54

Open question

The L_β line of X-rays emitted from an atom with principal quantum numbers n = 1, 2, 3, . . . . . . . ., arises from the transition

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Q55

Open question

Five energy levels of a system including the ground state are shown below. Their lifetimes and the allowed electric dipole transitions are also marked.
Atomic and Molecular Physics mcq question image

Atomic and Molecular Physics mcq question image

Which one of the following transitions is the most suitable for a Continuous Wave (CW) laser?

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Q56

Open question

When the refractive index

μ

of the active medium changes by

Δ μ

in a laser resonator of length L, the change in the spectral spacing between the longitudinal modes of the laser is (c is the speed of light in free space)

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Q57

Open question

The allowed states for He (2p²) configuration are

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Q58

Open question

For an electron in hydrogen atom, the states are characterized by the usual quantum numbers n,

l

, m_$l$. The electric dipole transition between any two states requires that

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Q59

Open question

Match the following:

P. Franck-Hertz experiment	1. Electronic excitation of molecules
Q. Hartree-Fock method	2. Wave function of atoms
R. Stern-Gerlach experiment	3. Spin angular momentum of atoms
S. Franck-Condon principle	4. Energy levels in atoms

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Q60

Open question

X-rays were produced using cobalt (Z = 27) as target. It was observed that the X-ray spectrum contained a strong K_α line of wavelength 0.1785 nm an a weak K_α line of wavelength 0.1930 nm. Then the weak K_α line is due to an impurity whose atomic number is

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