Thermodynamics practice · Mixed difficulty

Assertion: First law of thermodynamics is a restatement of the principle of conservation.
Reason: Energy is fundamental quantity.

An electric heater supplies heat to a system at a rate of $100 \mathrm{~W}$. If the system does work at a rate of $75 \mathrm{~J}$ per second, at what rate (in joules) is the internal energy increasing?

The mechanical equivalent of heat $J$ is

A gas at NTP is suddenly compressed to one fourth of its original volume. If $\gamma$ is supposed to be $3 / 2$, then the final pressure is :-

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

A gas expand $0.25\,\,{m^3}$ at constant pressure ${10^3}N/{m^2},$ the work done is

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

A water falls is 84 metres high. If half of the potential energy of the falling water get converted to heat, the rise in temperature of water will be

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

The specific heat at constant pressure of a real gas obeying $\mathrm{PV}^2=\mathrm{RT}$ equation is :

Two heat engines are operating in such a way that the heat rejected by the first engine is used as the heat input of the second. If both the engines are $40 \%$ efficient, then the overall efficiency of the system is

$100 \mathrm{~mol}$ 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?

Which of the following has maximum specific heat

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

Efficiency of Carnot engine is 100% if

When heat is given to a gas in an isothermal change, the result will be

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