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JEE Main 2020 (9 Jan, Shift 2) · Thermodynamic Processes

Thermodynamic Processes question from JEE Main 2020 (9 Jan, Shift 2)

Q210JEE Main 2020 · 9 JAN · SHIFT 2Difficult

Thermodynamic Processes

Starting at temperature 300 K, one mole of an

ideal diatomic gas (γ\gamma = 1.4) is first compressed

adiabatically from volume V1 to V2 = V116\frac{V_1}{16}. It is

then allowed to expand isobarically to volume 2V2. If all the processes are the quasi-static then the final temperature of the gas (in oK) is (to the nearest integer) _____.

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

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Answer: 1818

  1. Adiabatic: T2=T1(V1V2)γ−1=300×160.4T_2 = T_1\left(\frac{V_1}{V_2}\right)^{\gamma-1} = 300 \times 16^{0.4}
  2. 160.4=21.6≈3.0316^{0.4} = 2^{1.6} \approx 3.03, so T2≈909.4 KT_2 \approx 909.4\text{ K}.
  3. Isobaric: V∝TV \propto T, so doubling volume doubles temperature: T3=2×909.4≈1819 KT_3 = 2 \times 909.4 \approx 1819\text{ K}.
  4. Final temperature ≈1818\approx 1818–18191819 K.
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