Physics Circle home Student Login

Home›Chapters›Thermodynamics PYQs›Degrees of Freedom & Internal Energy›Question 8

JEE Main 2025 (2 Apr, Shift 2) · Degrees of Freedom & Internal Energy

Degrees of Freedom & Internal Energy question from JEE Main 2025 (2 Apr, Shift 2)

Q8JEE Main 2025 · 2 APR · SHIFT 2Medium

Degrees of Freedom & Internal Energy

The internal energy of air in 4 m×4 m×3 m4\text{ m} \times 4\text{ m} \times 3\text{ m} sized room at 1 atmospheric pressure will be___________________ ×106 J\times 10^{6}\text{ J}

(Consider air as diatomic molecule)

Numerical answer type. Work it out, then open the answer.

Show answer and solution

Answer: 12

  1. Diatomic air: U=52nRT=52PVU = \frac{5}{2}nRT = \frac{5}{2}PV.
  2. V=4×4×3=48 m3V = 4 \times 4 \times 3 = 48\ \text{m}^3, P=1.013×105P = 1.013 \times 10^5 Pa
  3. U=52×1.013×105×48≈12.2×106U = \frac{5}{2} \times 1.013 \times 10^5 \times 48 \approx 12.2 \times 10^6 J
  4. So the answer is 1212 (×106\times 10^6 J).
Report a mistake

More questions on Degrees of Freedom & Internal Energy