NEET Physics: specific heat capacities of gases Practice Questions
6 free multiple-choice questions on specific heat capacities of gases (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. If the specific heat capacity of a gas remains constant over a range of temperatures, what does this imply about the energy distribution within the gas molecules?
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Correct answer: A — The energy is distributed among the vibrational modes without increasing kinetic energy.
When specific heat capacity remains constant, it implies that the energy added to the gas is distributed among the internal degrees of freedom (like vibration or rotation) rather than increasing the translational kinetic energy significantly, maintaining the equipartition principle within the constraints of the system.
Q2. Which gas has the largest molar specific heat capacity among the following? (Assume ideal behavior)
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Correct answer: A — Oxygen (O₂)
The molar specific heat capacity depends on the number of degrees of freedom (f). Monatomic gases (f=3) have the smallest value, while polyatomic gases (f>3) have larger values. Oxygen (O₂) is a polyatomic gas and thus has a higher specific heat capacity than the monatomic gases (He, Ne, Ar).
Q3. The specific heat capacity of a monatomic ideal gas is equal to:
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Correct answer: D — 3R/2
For a monatomic gas (one degree of freedom per molecule), the molar specific heat at constant volume (Cᵥ) is 3/2R/mole.
Q4. Which statement is true regarding the specific heat capacities of ideal gases?
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Correct answer: B — Cₚ is always greater than Cᵥ
According to Mayer's relation (Cₚ - Cᵥ = R), since R is a positive constant, it must be true that Cₚ > Cᵥ for all ideal gases.
Q5. The translational kinetic energy of gas molecules is related to the total internal energy of the gas. How does the specific heat capacity of a gas depend on the number of degrees of freedom available to the molecules?
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Correct answer: B — It is directly proportional to the number of degrees of freedom.
According to the equipartition theorem, the molar specific heat capacity is directly proportional to the number of independent degrees of freedom. More degrees of freedom mean the system can store more energy, thus increasing the specific heat capacity.
Q6. Which gas has the highest molar specific heat capacity among the following diatomic gases (O₂, N₂, H₂)?
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Correct answer: A — O₂
Diatomic gases (N₂, O₂) have vibrational degrees of freedom in addition to translational degrees of freedom. Therefore, they possess higher heat capacity than monatomic gases. O₂ typically has a slightly higher vibrational contribution than N₂ for these simple comparisons.
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