Thermodynamics practice · Medium

Which of the following is true with regards to the energy of an isolated system?

Which of the following parameters does not characterise the thermodynamic state of matter?

(A): In isobaric process, during an expansion of a gas both volume and temperature of the gas increase.
(R): Heat added to a gas partly gets converted into internal energy and remaining to do external work.

Heat is not being exchanged in a body. If its internal energy is increased, then

(A): During a free expansion of an ideal gas work done is zero.
(R): Work done against vacuum is zero.

Conversion of water to steam is accompanied by which process?

A gas is heated at constant pressure. The fraction of heat energy used to increase the internal energy of the gas molecules is

Boyle’s law holds for an ideal gas during

The molar specific heat of a gas as given from the kinetic theory is $\frac{5}{2} R$. If it is not specified whether it is $C_p$ or $C_V$, one could conclude that the molecules of the gas

The ratio of the specific heats $\frac{C_p}{C_V}=\gamma$ in terms of degrees of freedom $(n)$ is given by

The change in internal energy of a thermodynamic system which has absorbed $2 \mathrm{kcal}$ of heat and done $400 \mathrm{~J}$ of work is (Take, $1 \mathrm{cal}=4.2 \mathrm{~J}$ )

An ideal gas has molar heat capacity $c_v$ at constant volume. The gas undergoes a process as $T=T_0\left(1+\alpha V^2\right)$ where $T$ and $V$ are temperature and volume respectively, $T_0$ and $\alpha$ are positive constants. The molar heat capacity $C$ of the gas is given as $C=C_V+R f(V)$, where $f(V)$ is a function of volume. The expression for $f(V)$ is

Efficiency of a heat engine is $\eta=0.4$ and the temperature of the source is $227^{\circ} \mathrm{C}$. If the temperature of source and sink increased by $100^{\circ} \mathrm{C}$, then the efficiency of a modified heat engine is

How much heat (in joules) is required to raise the temperature of $1 \mathrm{~g}$ of water from $14.5^{\circ} \mathrm{C}$ to $15.5^{\circ} \mathrm{C}$ at 1 atmospheric pressure?

In Which Process the PV indicator diagram is a straight line parallel to volume axis

During an adiabatic process, the cube of the pressure is found to be inversely proportional to the fourth power of the volume. Then the ratio of specific heats is

A system undergoes a cyclic process in which it absorbs $Q_1$ heat and gives out $Q_2$ heat. The efficiency of the process is $\eta$ and work done is $W$. Select the correct statement.

The molar heat capacity of a gas at constant volume is $C_V$. If $n$ moles of the gas undergo $\Delta T$ change in temperature, its internal energy will change by $n C_V \Delta T$

Assertion: The specific heat of a gas in an adiabatic process is zero and in an isothermal process is infinite.
Reason: Specific heat of a gas is directly proportional to change of heat in system and inversely proportional to change in temperature.

When the amount of work done is $333cal$ and change in internal energy is $167cal$, then the heat supplied is

A piece of ice (heat capacity=$2100JK{g^{ - 1}}^0{C^{ - 1}}$ and latent heat=$3.36 \times {10^5}\mathrm{Jk}{\mathrm{g}^{ - 1}}$) of mass m gram is at $- {5^0}C$ at atmospheric pressure. It is given 420 J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1 g of ice has melted. Assuming there is no other heat exchange in the process, the value of m is

An ideal gas goes through two different non cyclic quasistatic processes.

Process 1 $\rightarrow$ In this process change in internal energy is zero.

Process 2 $\rightarrow$ In this process work done by gas is zero.

Which is/are path dependent?

A system performs work ∆W when an amount of heat is $\Delta Q$ added to the system, the corresponding change in the internal energy is $\Delta U$. A unique function of the initial and final states (irrespective of the mode of change) is

When 20 K cal of heat is supplied to the system and the increase in the internal energy is 8400 J, then the work done by the system is

Statement-I: Two vessels A and B are connected to each other by a stopcock. Vessel A contains a gas at $300 \mathrm{~K}$ and 1 atmosphere pressure and vessel B is evacuated. The two vessels are thermally insulated from the surroundings. If the stopcock is suddenly opened, the expanding gas does no work.
Statement-II: Since $\Delta Q=0$ and as the gas expands freely so $\Delta W=0$ and from the first law of thermodynamics it follows that $\Delta U$ is also zero for the above process.

$n_1$ and $n_2$ are the moles of two ideal gases, whose thermodynamics constants, [ratio of $\left(\frac{C_p}{C_v}\right)$ ] are $\gamma_1$ and $\gamma_2$ respectively, are mixed. $\left(\frac{C_p}{C_v}\right)$ for the mixture is-

A gas mixture consists of 4 moles of $\mathrm{O}_2$ and 8 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:

If a gas is compressed adiabatically by doing work of $250 \mathrm{~J}$, the change in intemal energy of the gas is:

When a body A is in thermal equilibrium with a body B, and also separately with a body C, then B and C will be in thermal equilibrium with each other.