Question bank/JEE Main/Physics

JEE MainPhysicsModerateThermodynamics

The efficiency η\eta of the cyclic process
(γ=53)\left( \gamma = \frac{5}{3} \right) is given by 50n23\frac{50n}{23} then
find out the value of n.

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η50n23\eta\frac{50n}{23}gS rksn

Show answer and solution
η=W+Q\eta = \frac{W}{+ Q}
Temperature at A is T_0 then
P0V0=nRT0P_{0}V_{0} = {nRT}_{0}
T_0gS rks
P0V0=nRT0P_{0}V_{0} = {nRT}_{0}
at
TA=T0,TB=2T0,TC=6T0,TD=3T0T_{A} = T_{0},T_{B} = 2T_{0},T_{C} = 6T_{0},T_{D} = 3T_{0}
W=2P0V0W = 2P_{0}V_{0}
+Q=QAB+QBC+ Q = Q_{AB} + Q_{BC}
=n⋅CvdT+nCpdT= n \cdot C_{v}dT + nC_{p}dT
=32nRT0+52nR(4T0)= \frac{3}{2}{nRT}_{0} + \frac{5}{2}nR\left( 4T_{0} \right)
=232nRT0=232P0V0= \frac{23}{2}{nRT}_{0} = \frac{23}{2}P_{0}V_{0}
η=2P0V0232P0V0=423\eta = \frac{2P_{0}V_{0}}{\frac{23}{2}P_{0}V_{0}} = \frac{4}{23}

Source: Grass-G / Ph-26 Physics paper 1 15 Jan.docx

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