Thermodynamics practice · Mixed difficulty

What is the temperature of source in Carnot cycle of 10% efficiency when heat exhausts at 270 K?

Two cylinders of equal capacity are connected to each other via stop cock. $A$ contains an ideal gas at a standard temperature and pressure, $B$ is completely evacuated. The entire system is thermally insulated. The stop cock suddenly opens. Which one is correct option?

Assertion(A): In isothermal process, whole of the heat energy supplied to the body is converted into internal energy.

Reason(R): According to the first law of thermodynamics,

$\Delta Q=\Delta U+\Delta W$

The water of volume $4 \mathrm{~m}^3$ at the height $20 \mathrm{~m}$ is pressed by $2 \times 10^5 \mathrm{~N}$ pressure. The work done by motor is

10 moles of an ideal monoatomic gas at ${10^{^ \circ }}C$ is mixed with 20 moles of another monoatomic gas at ${20^ \circ }C.$ Then the temperature of the mixture is

(A): Thermodynamic process in nature are irreversible.
(R): Dissipative effects can not be eliminated.

One mole of helium is adiabatically expanded from its initial state $\left(P_i, V_i, T_i\right)$ to its final state $\left(P_f, V_f, T_f\right)$. The decrease in the internal energy associated with this expansion is equal to

The possibility of increase in the temperature of a gas without adding heat to it happens in:

The relation between energy $U$, pressure $P$ and volume $V$ for an ideal gas in an adiabatic process is given by, relation $U=a+b P V$. Find the value of adiabatic exponent $(\gamma)$ of this gas.

Even Carnot engine cannot give 100% efficiency because we cannot

The mechanical equivalent of heat $J$ is

A heat engine is a device

An ideal monoatomic gas at ${27^ \circ }C$ is compressed adiabatically to 8/27 times of its present volume. The increase in temperature of the gas is

A container of volume $1\,\,{{\text{m}}^3}$ is divided into two equal compartments, one of which contains an ideal gas at 400 K. The other compartment is vacuum. The whole system is thermally isolated from its surroundings. The partition is removed and the gas expands to occupy the whole volume of the container. Its temperature now would be

When heat energy of $1500joules$, is supplied to a gas at constant pressure$2.1 \times {10^5}N/{m^2}$, there was an increase in its volume equal to $2.5 \times {10^{ - 3}}N/{m^2}$. The increase in internal energy of the gas in joules is

(A): During an adiabatic compression temperature of an ideal gas increases.
(R): Internal energy of a gas can be changed even without addition or withdrawn of heat but by doing work.

When a mole of an ideal gas expands isothermally at $27^\circ C$ to double its original volume, the work done by the gas is $\left[ {R = 8.314\,\,\,{{\deg }^{ - 1}}\,{\text{mo}}{{\text{l}}^{ - 1}}} \right]\left[ {\log _{10}^2 = 0.3010} \right]$

Assertion: first law of thermodynamics allows many processes which actually don't happen.
Reason: First law of thermodynamics must not be violated for any process to happen.

In which of the following processes, heat is neither absorbed nor released by a system?

When gas in a vessel expands its internal energy decreases. The process involved is

Statement-I: According to Joule, heat and work are related
Statement-II: For every $1 \mathrm{~Cal}$ of heat we can get $4.186 \mathrm{~J}$ of mechanical work.

A cylinder of mass $1kg$ is given heat of $20000J$ at atmospheric pressure. If initially temperature of cylinder is ${20^ \circ }C$, then work done by the cylinder will be (Given that Specific heat of cylinder $= 400J k{g^{ - 1}}$), Coefficient of volume expansion $= 9 \times {10^{ - 5}}^ \circ {C^{ - 1}}$, Atmospheric pressure$= {10^5}N/{m^2}$ and density of cylinder $9000kg/{m^3}$)

A Carnot engine whose low-temperature reservoir is at ${27^ \circ }C$ has efficiency $37.5\%$. The high-temperature reservoir is at

Assertion: Specific heat of any substance remains constant at all temperatures.

Reason : It is given by $s=\frac{1}{m} \cdot \frac{d Q}{d T}$

Following statements are given:
(A) The average kinetic energy of a gas molecule
decreases when the temperature is reduced.
(B) The average kinetic energy of a gas molecule
increases with increase in pressure at constant
temperature.
(C) The average kinetic energy of a gas molecule
decreases with increase in volume.
(D) Pressure of a gas increases with increase in
temperature at constant pressure.
(E) The volume of gas decreases with increase in
temperature.
Choose the correct answer from the options given
below:

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

An ideal gas undergoes a reversible isothermal expansion from a state i to f. The change in entropy $\Delta s\left( {i \to f} \right)$ is

If $c_p$ and $c_v$ denote the specific heats (per unit mass of an ideal gas of molecular weight $M$), then

The specific heat at constant pressure is greater than that of the same gas at constant volume because

The thermodynamic process, in which internal energy of the system remains constant is