Thermodynamics practice · Medium

Compressed air in the tube of a wheel of a cycle at normal temperature suddenly starts coming out from a puncture. The air inside

During an adiabatic expansion of 2 moles of a gas, the change in internal energy was found $- 50J$.The work done during the process is

An engineer claims to have made an engine delivering $10kW$ power with fuel consumption of $1g/s$. The calorific value of the fuel is $2kcal/g$. Is the claim of the engineer

Statement-1: When you touch two bodies, the body which is felt warmer must be of higher temperature than the other one.
Statement-2: The heat flows from higher temperature to lower temperature.

In an isothermal change, an ideal gas obeys

For a gas, the difference between the two principle specific heats is 4150 $\mathrm{Jk}{\mathrm{g}^{ - 1}}{\mathrm{K}^{ - 1}}$.What is the specific heat of the gas at constant volume if the ratio of specific heat is 1.4?

Which of the following is not a thermodynamical function

An ideal monoatomic gas $\mathrm{A}$ is supplied heat so as to expand without changing its temperature. In another process, starting with same state, it is supplied heat at constant pressure. In both cases a graph of work done by gas is plotted versus heat added (Q) to the gas. The ratio of slope of graphs obtained in first & second process in $\eta_1$. The same ratio obtained for ideal diatomic gas is $\eta_2$. If the ratio $\frac{\eta_1}{\eta_2}=\frac{a}{b}$. Then find $a+b$.

Assertion: The zeroth law said that, when two systems $X$ and $Y$ are in thermal equilibrium, there must be a physical quantity that has the same value for both.
Reason: The physical quantity, which is same for both the systems, is temperature.

The specific heat relation for ideal gas is

Assertion: The ratio $\frac{C_P}{C_V}$ is more for helium gas than for hydrogen gas.
Reason: Atomic mass of helium is more than that of hydrogen.

The mechanical equivalent of heat $J$ is

500 J of heat energy is removed from 4 moles of a monoatomic ideal gas at constant volume. The temperature drops by

Assertion: Heat is not a state thermodynamic function.
Reason: Heat given in a system depends on process.

A Carnot’s engine works as a refrigerator between 250 K and 300 K. It receives 500 cal heat from the reservoir at the lower temperature. The amount of work done in each cycle to operate the refrigerator is

Entropy of a system is related with

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

The factor not needed to calculate heat lost or gained when there is no change of state is

Calculate the time required to heat $20 \mathrm{~kg}$ of water from $10^{\circ} \mathrm{C}$ to $35^{\circ} \mathrm{C}$ using an immersion heater rated $1000 \mathrm{~W}$. Assume that $80 \%$ of the power input is used to heat the water. Specific heat capacity of water $=4200 \mathrm{~J} \mathrm{~kg}^{-1} \mathrm{~K}^{-1}$.

Pressure – Temperature relationship for an ideal gas undergoing adiabatic change is $\left( {\gamma = \frac{{{C_P}}}{{{C_V}}}} \right)$

A gas under constant pressure of $4.5 \times {10^5}$ Pa when subjected to 800 kJ of heat changes the volume from$0.5{\mathrm{m}^3}$ to $2.0{\mathrm{m}^3}$. The change in the internal energy of the gas is

The energy supply being cut-off, an electric heater element cools down to the temperature of its surroundings, but it will not cool further because

$100 \mathrm{~mol}$ of an ideal gas is heated from $10^{\circ}$ to $20^{\circ} \mathrm{C}$ keeping its (i) volume constant (ii) pressure constant. Let $\Delta U_a$ and $\Delta U_b$ denote the change in the internal energy of the gas due to process (i) and (ii), respectively. Then, which of the following shall be true?

The first operation involved in a carnot cycle is

Heat energy of $184 \mathrm{~kJ}$ is given to ice of mass $600 \mathrm{~g}$ at $-12^{\circ} \mathrm{C}$. Specific heat of ice is $2222.3 \mathrm{~J} \mathrm{~kg}^{-}$ ${ }^{10} \mathrm{C}^{-1}$ and latent heat of ice in $336 \mathrm{~kJ} / \mathrm{kg}^{-1}$

A. Final temperature of system will be $0^{\circ} \mathrm{C}$.

B. Final temperature of the system will be greater than $0^{\circ} \mathrm{C}$.

C. The final system will have a mixture of ice and water in the ratio of $5: 1$.

D. The final system will have a mixture of ice and water in the ratio of $1: 5$.

E. The final system will have water only.

Choose the correct answer from the options given below:

The ideal gas equation for an adiabatic process is:

${C_v}and{C_p}$ denote the molar specific heat capacities of a gas at constant volume and constant pressure, respectively. Then

How much work to be done in decreasing the volume of an ideal gas by an amount of $2.4 \times {10^{ - 4}}{m^3}$ at normal temperature and constant normal pressure of $1 \times {10^5}N/{m^2}$

Two Carnot engines A and B are operated in series. The engine $A$ receives heat from the source at temperature $T_1$ and rejects the heat to the sink at temperature $\mathrm{T}$. The second engine $B$ receives the heat at temperature $T$ and rejects to its sink at temperature $T_2$. For what value of $T$ the efficiencies of the two engines are equal?

An ideal monoatomic gas undergoes process $P V^{1.25}=$ Constant . Then