In the p-V diagram below,the dashed curved li | vedclass

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(C) The first law of thermodynamics states that $dQ = dU + dW$. For an ideal gas,$dU = nC_v dT$. Along the straight line path $XY$,the system moves th

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absorbed from $X$ up to an intermediate point $Z$ (not shown in the figure) and then released from $Z$ to $Y$

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(C) The first law of thermodynamics states that $dQ = dU + dW$. For an ideal gas,$dU = nC_v dT$. Along the straight line path $XY$,the system moves through different isotherms. At the start point $X$ and end point $Y$,the temperature is the same as they lie on the same adiabat (if we consider the adiabat as a boundary). However,as the straight line path $XY$ lies above the adiabat,the temperature of the gas first increases as it moves away from the adiabat towards higher temperature isotherms,reaching a maximum at some intermediate point $Z$,and then decreases as it approaches point $Y$. Since $dQ = nC_v dT + p dV$,and $dV > 0$ throughout the process,the heat exchange depends on the sign of $dT$. From $X$ to $Z$,the temperature increases $(dT > 0)$,so heat is absorbed. From $Z$ to $Y$,the temperature decreases $(dT < 0)$,and the work done by the gas eventually outweighs the internal energy change,leading to heat release. Thus,heat is absorbed from $X$ to $Z$ and released from $Z$ to $Y$.

In the $p-V$ diagram below,the dashed curved line is an adiabat. For a process that is described by a straight line joining two points $X$ and $Y$ on the adiabat (solid line in the diagram),heat is (Hint: consider the variation in temperature from $X$ to $Y$ along the straight line)

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