List of top Physics Questions on Thermodynamics asked in IIT JAM PH

One kg of water at 27$^\circ$C is brought in contact with a heat reservoir kept at 37$^\circ$C. Upon reaching thermal equilibrium, this mass of water is brought in contact with another heat reservoir kept at 47$^\circ$C. The final temperature of water is 47$^\circ$C. The change in entropy of the whole system in this entire process is \rule{1cm{0.15mm} cal/K. (up to two decimal places)
Take specific heat at constant pressure of water as 1 cal/(g K)}

Three gaseous systems, $G_1, G_2$, and $G_3$ with pressure and volume ($P_1, V_1$), ($P_2, V_2$), and ($P_3, V_3$), respectively, are such that
(I) when $G_1$ and $G_2$ are in thermal equilibrium, $P_1V_1 - P_2V_2 + \alpha P_2 = 0$, is satisfied, and
(II) when $G_1$ and $G_3$ are in thermal equilibrium, $P_3V_3 - P_1V_1 + \frac{\beta P_1V_1}{V_3} = 0$, is satisfied.
The relation(s) valid at thermal equilibrium is(are)
($\alpha$ and $\beta$ are constants of appropriate dimensions)

An ideal mono-atomic gas is expanded adiabatically from A to B. It is then compressed in an isobaric process from B to C. Finally, the pressure is increased in an isochoric process from C to A. The cyclic process is shown in the figure below. For this system, which of the following is(are) correct?

Consider Maxwell's relation $ \left(\frac{\partial S}{\partial V}\right)_T = \left(\frac{\partial P}{\partial T}\right)_V $. The equation of state of a thermodynamic system is given as $ P = \frac{AT}{\sqrt{V}} + \frac{BT^3}{V} $, where A and B are constants of appropriate dimensions. Then $ \left(\frac{\partial C_V}{\partial V}\right)_T $ of the system varies with temperature as ($C_V$ is the heat capacity at constant volume)

Consider two spherical perfect blackbodies with radii $R_1$ and $R_2$ at temperatures $T_1 = 1000\, \text{K}$ and $T_2 = 2000\, \text{K}$, respectively. They both emit radiation of power 1 kW. The ratio of their radii, $R_1/R_2$, is given by ...............

A body at a temperature $T$ is brought into contact with a reservoir at temperature $2T$. Thermal equilibrium is established at constant pressure. The heat capacity of the body at constant pressure is $C_p$. The total change in entropy of the body and the reservoir in units of $C_p$ is ............ (Round off to 2 decimal places)

One mole of an ideal monatomic gas at pressure $P$, volume $V$ and temperature $T$ is expanded isothermally to volume $4V$. Thereafter, the gas is heated isochorically (at constant volume) till its pressure becomes $P$. If $R$ is the universal gas constant, the total heat transfer in the process, in units of $RT$, is ................... (Round off to 2 decimal places)

One mole of an ideal gas having specific heat ratio ($\gamma$) of 1.6 is mixed with one mole of another ideal gas having specific heat ratio of 1.4. If $C_V$ and $C_P$ are the molar specific heat capacities of the gas mixture at constant volume and pressure, respectively, which of the following is/are correct? ($R$ denotes the universal gas constant.)

An ideal gas undergoes an isothermal expansion along path AB, adiabatic expansion along BC, isobaric compression along CD, isothermal compression along DE, and adiabatic compression along EA, as shown in the figure. The work done by the gas along the process BC is 10 J. The change in the internal energy along process EA is 16 J. The absolute value of the change in the internal energy along the process CD is ............ J.

For a system undergoing a first-order phase transition at a temperature $T_c$, which one of the following graphs best describes the variation of entropy (S) as a function of temperature (T)?

Which one of the figures correctly represents the T–S diagram of a Carnot engine?

A monoatomic ideal gas undergoes a closed cycle shown in the P–V diagram. The ratio $\frac{P_2}{P_1}$ is ........... (Specify your answer up to two digits after the decimal point.)

Which of the following relations is (are) true for thermodynamic variables?

The equation of state for one mole of a non-ideal gas is given by $PV = A\left(1 + \dfrac{B}{V}\right)$, where the coefficients $A$ and $B$ are temperature dependent. If the volume changes from $V_1$ to $V_2$ in an isothermal process, the work done by the gas is

Consider an ensemble of thermodynamic systems, each of which is characterized by the same number of particles, pressure and temperature. The thermodynamic function describing the ensemble is