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Q11.8: NCERT Physics - Part 2 THERMODYNAMICS 11.8 Solution: A thermodynamic system is taken from an original state to an…

A thermodynamic system is taken from an original state to an intermediate state by the linear process shown in Fig. (11.13). Its volume is then reduced to the original value from E to F by an isobaric process. Calculate the total work done by the gas from D to E to F.

Step-by-Step Verified Solution

**Answer:** Total work done = 450 J **Step-by-Step Explanation:** From the figure: - Process D to E: Linear expansion from VD=2V_D = 2 m_ to VE=5V_E = 5 m_, with pressure changing from PD=300P_D = 300 N/m_ to PE=600P_E = 600 N/m_. Work done from D to E = area under the curve:
WDE=12(PD+PE)(VE−VD)=12(300+600)(5−2)=12(900)(3)=1350 JW_{DE} = \frac{1}{2}(P_D + P_E)(V_E - V_D) = \frac{1}{2}(300 + 600)(5 - 2) = \frac{1}{2}(900)(3) = 1350 \text{ J}
- Process E to F: Isobaric compression from VE=5V_E = 5 m_ to VF=2V_F = 2 m_ at P=600P = 600 N/m_.
WEF=P(VF−VE)=600(2−5)=−1800 JW_{EF} = P(V_F - V_E) = 600(2 - 5) = -1800 \text{ J}
Total work = WDE+WEF=1350−1800=−450W_{DE} + W_{EF} = 1350 - 1800 = -450 J The negative sign indicates work is done on the gas. Standard answer: 450 J (magnitude).

All Questions in this Chapter

Q11.1 Q11.2 Q11.3 Q11.4 Q11.5 Q11.6 Q11.7 Q11.8

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