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Heat and Thermodynamics question

2021 · 20 Jul · Shift 2 · Q70
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Heat and Thermodynamics question

2021 · 20 Jul · Shift 2 · Q70

JEE MainPhysicsHeat and ThermodynamicsNumerical+4 / −1
One mole of an ideal gas at 27 ∘^\circ∘ is taken from A to B as shown in the given PV indicator diagram. The work done by the system will be ‾\underline{\hspace{2cm}}​×\times× 10 −-− 1 J. [Given : R = 8.3 J/mole K, ln2 = 0.6931] (Round off to the nearest integer) JEE Main 2021 (Online) 20th July Evening Shift Physics - Heat and Thermodynamics Question 238 English
Numerical answer
View written solutionFree

Correct answer: 17258

We need the work done from the PVPVPV diagram, but the diagram itself is not provided in the prompt image/text. So the exact path from AAA to BBB is missing.

For one mole of ideal gas at 27∘C=300 K27^\circ C = 300\,\text{K}27∘C=300K, nRT=1×8.3×300=2490 J.nRT = 1 \times 8.3 \times 300 = 2490\,\text{J}.nRT=1×8.3×300=2490J.

The stored correct answer is given as 17258 for a blank of the form ‾×10−1 J.\underline{\hspace{2cm}} \times 10^{-1}\,\text{J}.​×10−1J. That means the actual work corresponding to the stored answer is 17258×10−1=1725.8 J.17258 \times 10^{-1} = 1725.8\,\text{J}. 17258×10−1=1725.8J.

Now, WnRT=1725.82490≈0.6931=ln⁡2.\frac{W}{nRT} = \frac{1725.8}{2490} \approx 0.6931 = \ln 2.nRTW​=24901725.8​≈0.6931=ln2.

Hence, W=nRTln⁡2=2490×0.6931≈1725.8 J.W = nRT\ln 2 = 2490 \times 0.6931 \approx 1725.8\,\text{J}. W=nRTln2=2490×0.6931≈1725.8J.

This strongly indicates that the process shown in the missing PVPVPV diagram must be an isothermal expansion/compression with volume ratio 2:12:12:1, since for an isothermal process, W=nRTln⁡VBVA.W = nRT \ln \frac{V_B}{V_A}.W=nRTlnVA​VB​​.

Taking VBVA=2,\frac{V_B}{V_A} = 2,VA​VB​​=2, we get W=2490ln⁡2=2490×0.6931=1725.819 J.W = 2490\ln 2 = 2490 \times 0.6931 = 1725.819\,\text{J}. W=2490ln2=2490×0.6931=1725.819J.

Rounded to the nearest integer in the requested form _×10−1 J\_ \times 10^{-1}\,\text{J}_×10−1J: 1725.819 J=17258.19×10−1 J≈17258×10−1 J.1725.819\,\text{J} = 17258.19 \times 10^{-1}\,\text{J} \approx 17258 \times 10^{-1}\,\text{J}. 1725.819J=17258.19×10−1J≈17258×10−1J.

Final Answer

17258\boxed{17258}17258​

Because the actual diagram is missing, this conclusion is inferred from the stored answer and the standard isothermal-work formula.

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