An ideal gas has undergone through the cyclic process as shown in the figure. Work done by the gas in the entire cycle is ______ ×10−1 J. (Take π=3.14)
Answer: 314
Solution
For a closed cycle the work done by the gas equals the area enclosed in the P--V plane. The loop is an ellipse centred at 400 kPa and 250cm3, with pressure semi-axis (500−300)/2=100kPa=105 Pa and volume semi-axis (350−150)/2=100cm3=10−4m3. The enclosed area is
W=π(105)(10−4)=π×10=31.4J.
In the units asked, the work done in the cycle is 314×10−1 J.
