Thermodynamics practice · Medium

If the amount of heat given to a system is $35J$and the amount of work done on the system is $15J$, then the change in internal energy of the system is

The isothermal Bulk modulus of an ideal gas at pressure $P$ is

Two kg of water is converted into steam by boiling at atmospheric pressure. The volume changes from $2 \times {10^{ - 3}}{m^3}$ to $3.34{m^3}$. The work done by the system is about

Statement-I: It is impossible to derive continuous supply of work by cooling a body to a temperature lower than that of the coldest of its surroundings
Statement-II: Heat engine can convert whole of the heat energy supplied to it into useful work

Isobaric modulus of elasticity is equal to

An adiabatic cylindrical tube of cross-sectional area $1 \mathrm{~cm}^2$ is closed at one end and fitted with a piston at the other end. The tube contains $0.03 \mathrm{~g}$ of an ideal gas. At $1 \mathrm{~atm}$ pressure and at the temperature of the surrounding, the length of the gas column is $40 \mathrm{~cm}$. The piston is suddenly pulled out to double the length of the column. The pressure of the gas falls to $0.355 \mathrm{~atm}$. Find the speed of sound in the gas at atmospheric temperature.

A sample of perfect gas is compressed isothermally to half its volume. If it is compressed adi-abatically to the same volume, the final pressure of the gas will be:

Assertion: In an adiabatic process work done by an ideal gas equals change in its internal energy.
Reason: In an adiabatic process, temperature of system and surrounding remains same.

Assertion: Water kept in an open vessel will quickly evaporate on the surface of the moon.
Reason: There is lack of atmospheric pressure at surface of moon.

The pressure of an ideal gas varies with volume as $P = \alpha V,$ where $\alpha$ is a constant. One mole of the gas is allowed to undergo expansion such that its volume becomes $'m'$ times its initial volume. The work done by the gas in the process is

For adiabatic expansion of a monoatomic perfect gas, the volume increases by 2.4%. The percentage decrease in pressure is

Boiling water is changing into steam. At this stage then specific heat of water is

The following sets of values for ${C_V}$ and ${C_P}$ of a gas has been reported by different students. The units are $cal/g$-$mole$-$K.$ Which of these sets is most reliable

Two cylinders $\mathrm{A}$ and $\mathrm{B}$ of equal capacity are connected to each other via a stop cock. $\mathrm{A}$ contains an ideal gas at
standard temperature and pressure. $\mathrm{B}$ is completely evacuated. The entire system is thermally insulated. The stop
cock is suddenly opened. The process is:

If specific heat of a substance is infinite, it means

Statement-I: According to the second law of thermodynamics total heat can be converted into mechanical work
Statement-II: Due to various losses, it is impossible to convert total heat into mechanical work

The gas law $\frac{{PV}}{T}$ = constant is true for

The temperature of the source of a Carnot's heat engine is $1000^{\circ} \mathrm{C}$. Its efficiency could be $100 \%$ only if the temperature of the sink is

(A): When a glass of hot milk is placed in a room and allowed to cool, its entropy decreases.
(R): Allowing hot object to cool does not violate the second law of thermodynamics.

A flask contains argon and oxygen in the ratio of 3 : 2 in mass and the mixture is kept at $27^\circ C.$ The ratio of their average kinetic energy per molecule respectively will be

Assertion: Air pressure in a car type increases during driving.
Reason: Absolute zero temperature is not zero energy temperature.

Second law of efficiency is defined as:

Assertion: The value of $\Delta Q$ is always zero inadiabatic process.
Reason: Adiabatic process is always a cyclic process.

A gas is suddenly expanded such that its final volume becomes 3 times its initial volume. If the specific heat at constant volume of the gas is 2$R$, then the ratio of initial to final pressure is nearly equal to

STATEMENT(A): A quasi-static process is
an infinitely slow process such that the
system remains in thermal and mechanical
equilibrium with the surroundings
throughout.

STATEMENT(B): Spontaneous processes of
nature are irreversible.

5 mole of an ideal gas with $(\gamma = 7/5)$ initially at STP are compressed adiabatically so that its temperature becomes ${400^ \circ }C$ .The increase in the internal energy of gas in kJ is

Heat is given to an ideal gas in an isothermal process.

A. Internal energy of the gas will decrease.

B. Internal energy of the gas will increase.

C. Internal energy of the gas will not change.

D. The gas will do positive work.

E. The gas will do negative work.

Choose the correct answer from the options given below:

Assertion: In free expansion of an ideal gas internal energy is constant.
Reason: No heat is added and no work is done in free expansion.

By opening the door of a refrigerator inside a closed room

A Carnot engine with its cold body at $17^{\circ} \mathrm{C}$ has $50 \%$ efficiency. If the temperature of its hot body is now increased by $145^{\circ} \mathrm{C}$, the efficiency becomes