Atomic and Molecular Physics MCQs Question and Answer in Engineering Physics

The vibrational spectrum of a molecule exhibits a strong line with P and R branches at a frequency $${\nu _1}$$ and a weaker line at a frequency $${\nu _2}$$ . The frequency $${\nu _3}$$ is not shown up. Its vibrational Raman spectrum shows a strongly polarized line at frequency $${\nu _3}$$ and no feature at $${\nu _1}$$ and $${\nu _2}$$ .
Which of the following statements is correct?

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

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

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

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

In hyperfine interaction, there is coupling between the electron angular momentum $$\overrightarrow {\bf{J}} $$ and nuclear angular momentum $$\overrightarrow {\bf{I}} $$, forming resultant angular momentum $$\overrightarrow {\bf{F}} $$. The selection rules for the corresponding quantum number F in hyperfine transitions are

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

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)

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

The degeneracy of the spectral term ³f is