Atomic and Molecular Physics MCQs with Answers 2027

Q61

The vibrational spectrum of a molecule exhibits a strong line with P and R branches at a frequency

ν_{1}

and a weaker line at a frequency

ν_{2}

. The frequency

ν_{3}

is not shown up. Its vibrational Raman spectrum shows a strongly polarized line at frequency

ν_{3}

and no feature at

ν_{1}

and

ν_{2}

.
Which of the following statements is correct?

Select an option to see the answer and solution.

Q62

Open question

The short wavelength, cut-off of the continuous X-ray spectrum from a nickel target is 0.0825 nm. The voltage required to.be applied to an X-ray tube is

Select an option to see the answer and solution.

Q63

Open question

The allowed rotational energy levels of a rigid hetero-nuclear diatomic molecule are expressed as ε_J = BJ (J + 1), where B is the rotational constant and J is a rotational quantum number.
In a system of such diatomic molecules of reduced mass μ, some of the atoms of one element are replaced by a heavier isotope, such that the reduced mass is changed to 1.05μ. In the rotational spectrum of the system, the shift in the spectral line, corresponding to a transition J = 4 → J = 5, is

Select an option to see the answer and solution.

Q64

Open question

The degeneracies of the J-states arising from the ³p term with spin-orbit interaction are

Select an option to see the answer and solution.

Q65

Open question

The sodium doublet lines are due to transitions from ²p_3/2 and ²p_1/2 levels to ²s_1/2 level. On application of a weak magnetic field, the total number of allowed transitions becomes

Select an option to see the answer and solution.

Q66

Open question

In hyperfine interaction, there is coupling between the electron angular momentum

J

and nuclear angular momentum

I

, forming resultant angular momentum

F

. The selection rules for the corresponding quantum number F in hyperfine transitions are

Select an option to see the answer and solution.

Q67

Open question

The hyperfine splitting of the spectral lines of an atom is due to

Select an option to see the answer and solution.

Q68

Open question

Three consecutive absorption lines at 64.275 cm^-1, 77.130 cm^-12 and 89.985 cm^-1 have been observed in a microwave spectrum for a linear rigid diatomic molecule. The moments of inertia

I_{A}

and

I_{B}

are (

I_{A}

is with respect to the bond axis passing through the centre of mass and

I_{B}

is with respect to an axis passing through the centre of mass and perpendicular to bond axis)

Select an option to see the answer and solution.

Q69

Open question

The L, S and J quantum numbers corresponding to the ground state electronic configuration of boron (Z = 5) are

Select an option to see the answer and solution.

Q70

Open question

The degeneracy of the spectral term ³f is

Select an option to see the answer and solution.

Q71

Open question

Assuming that the L-S coupling scheme is valid, the number of permitted transitions from ²P_3/2 to ²s_1/2 due to a weak magnetic field is

Select an option to see the answer and solution.

Q72

Open question

The D₁ and D₂ lines of Na(3²p_1/2 → 3²s_1/2, 3²p_3/2 → 3²s_1/2) will split on the application of a weak magnetic field into

Select an option to see the answer and solution.

Q73

Open question

The NMR spectrum of ethanol (CH₃CH₂OH) comprises of three bunches of spectral lines. The number of spectral lines in the bunch corresponding to CH₂ group is

Select an option to see the answer and solution.

Q74

Open question

In the microwave spectrum of identical rigid diatomic molecules, the separation between the spectral lines is recorded to be 0.7143 cm^-1. The moment of inertia of the molecule, in kg-m² is

Select an option to see the answer and solution.

Q75

Open question

The typical wavelengths emitted by diatomic molecules in purely vibrational and purely rotational transitions are respectively in the region of

Select an option to see the answer and solution.

Q76

Open question

The target of an X-ray tube is subjected to an excitation voltage V. The wavelength of the emitted X-rays is proportional to

Select an option to see the answer and solution.

Q77

Open question

In a two-electron atomic system having orbital and spin angular momenta

l_{1} l_{2}

and

s_{1} s_{2}

respectively, the coupling strengths are defined as

Γ_{l_{1} l_{2}}, Γ_{s_{1} s_{2}}, Γ_{l_{1} s_{1}}, Γ_{l_{2} s_{2}}, Γ_{l_{1} l_{2}}

and

Γ_{l_{2} s_{1}} .

For the jj coupling. scheme to be applicable, the coupling strengths must satisfy the condition

Select an option to see the answer and solution.

Atomic and Molecular Physicspractice.

Atomic and Molecular Physics
practice.