NEET Physics: Degrees of freedom Practice Questions
15 free multiple-choice questions on Degrees of freedom (Kinetic Theory of Gases) for NEET Physics, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. The rotational degrees of freedom for a linear molecule are:
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Correct answer: B — 2
A linear molecule can rotate about two axes perpendicular to the molecular axis, giving 2 rotational degrees of freedom.
Q2. In the context of kinetic theory, what physical motion corresponds to the vibrational degrees of freedom of a gas molecule?
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Correct answer: B — Movement along the bond axis
Vibrational degrees of freedom represent the stretching and compression of the intramolecular bonds along the molecular axis.
Q3. The number of vibrational degrees of freedom available in a non-linear molecule is typically related to the number of atoms and their bonds. What is the general relationship for vibration for a molecule with N atoms?
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Correct answer: C — 3N-6
For a non-linear molecule, the degrees of freedom associated with vibration and rotation often depend on the number of atoms, typically 3N-6 (if we consider only vibrational modes relevant to internal energy).
Q4. A monatomic gas molecule possesses which type of degree of freedom?
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Correct answer: B — Translational only
Monatomic molecules have no internal bonds or rotational motion, thus they only exhibit translational degrees of freedom (motion in 3 spatial directions).
Q5. How many degrees of freedom does a rigid sphere (like an atom) have in terms of rotation, assuming no translation?
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Correct answer: B — 3
A rigid sphere has three spatial dimensions. Rotation around all three axes yields 3 rotational degrees of freedom.
Q6. The total number of degrees of freedom for a linear diatomic molecule is:
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Correct answer: C — 7
For a linear diatomic molecule (like O2), there are 3 translational DOF and 2 rotational DOF, resulting in a total of 5 DOF.
Q7. The translational degrees of freedom for any molecule are determined by:
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Correct answer: C — The number of dimensions
Translational freedom relates to the movement along the x, y, and z axes, which corresponds to 3 spatial dimensions.
Q8. A linear molecule (like CO₂) has rotational degrees of freedom. How many rotational degrees of freedom does it possess?
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Correct answer: C — 2
A linear molecule can rotate around two axes perpendicular to the molecular axis, giving it two rotational degrees of freedom.
Q9. A molecule that possesses no rotational degrees of freedom is classified as a:
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Correct answer: B — Monatomic molecule
Rotational degrees of freedom arise from the rotation of the molecule about its center of mass. A molecule with no rotational freedom is monatomic.
Q10. The total degrees of freedom for a polyatomic gas molecule, such as N₂ (a diatomic molecule), consists of translational and rotational modes of motion. How many degrees of freedom does a diatomic molecule possess?
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Correct answer: B — 5
A diatomic molecule has 3 translational degrees of freedom (motion along x, y, z) and 2 rotational degrees of freedom (rotation about the two axes perpendicular to the bond). Total degrees of freedom = 3 + 2 = 5.
Q11. The kinetic energy of the gas molecules is related to the total degrees of freedom by which principle?
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Correct answer: C — Kinetic Theory of Gases
The Kinetic Theory of Gases postulates that the total internal energy (and thus kinetic energy) of the gas is directly related to the motion of the constituent molecules, quantified by their degrees of freedom.
Q12. In the kinetic theory of gases, what is the number of translational degrees of freedom for a single gas molecule moving in three-dimensional space?
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Correct answer: C — 3
Translational motion along the x, y, and z axes constitutes three independent degrees of freedom (one for each direction).
Q13. A polyatomic gas molecule like CO₂ has which total degrees of freedom?
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Correct answer: C — 5
A polyatomic molecule has 3 translational degrees of freedom and 3 rotational degrees of freedom (since it is not linear). Total DOF = 3 + 3 = 6.
Q14. A diatomic gas molecule has how many degrees of freedom?
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Correct answer: C — 5
A diatomic molecule has 3 translational degrees of freedom and 2 rotational degrees of freedom, totaling 5 degrees of freedom.
Q15. How many rotational degrees of freedom does a non-linear polyatomic molecule possess?
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Correct answer: A — 2
A non-linear molecule (like H₂O) has three distinct axes of rotation (around the three principal moments of inertia), giving it 3 rotational degrees of freedom.
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