Heat and Thermodynamics

Assertion : In adiabatic process work is
independent of the path.
Reason : In adiabatic process work done is
equal to negative of change in internal
energy.

Assertion : \(\mathrm{NH}_3\) is liquidities more easily than \(\mathrm{CO}_2\).
Reason : Critical temperature of \(\mathrm{NH}_3\) is more than \(\mathrm{CO}_2\).

Assertion : Vibrational degree of freedom of
a di-atomic gas molecule appears at every
high temperature.
Reason : Di-atomic gas has two vibrational
degree of freedom in one direction.

An ideal gas initially at pressure 1 bar is being compressed from \(30 \mathrm{~m}^3\) to \(10 \mathrm{~m}^3\) volume and its temperature decreases from \(320 \mathrm{~K}\) to \(280 \mathrm{~K}\), then find final pressure of the gas.

Calculate radiation power for sphere whose temperature is 227\(^\circ\)C, radius 2 m and emissivity 0.8.

In an isobaric process, the work done by a
di-atomic gas is 10 J, the heat given to the
gas will be

If \(7 \mathrm{~gm} \mathrm{~N}_2\) is mixed with \(20 \mathrm{~gm} \mathrm{~Ar}\), there \(\frac{C_p}{C_V}\) of mixture will be

The temperature of food material in
refrigerator is 4\(^\circ\)C and temperature of
environment is 15\(^\circ\)C. If carnot cycle is used
in its working gas, then find its carnot
efficiency.

Assertion Internal energy of an ideal gas
does not depend on volume of gas.
Reason Internal energy depends only on
temperature of gas.

Assertion In isothermal process, whole of
the heat energy supplied to the body is
converted into internal energy.
Reason According to the first law of
thermodynamics,
\(\Delta Q=\Delta U+\Delta W\)

A gas consisting of a rigid diatomic molecules
was initially under standard condition. Then,
gas was compressed adiabatically to
one-fifth of its initial volume. What will be
the mean kinetic energy of a rotating
molecule in the final state...

An ideal gas of mass \(m\) in a state \(A\) goes to another state \(B\) via three different processes as shown in figure. If \(Q_1, Q_2\) and \(Q_3\) denote the heat absorbed by the gas along the three paths, then

Assertion : Molar heat capacity cannot be defined for isothermal process.
Reason : In isothermal process \(p\)-\(V\) versus \(T\) graph is a dot.

Assertion : The molecules of a monoatomic gas has three degrees of freedom.
Reason : The molecules of diatomic gas has five degrees of freedom.

Assertion : In adiabatic expansion the product of \(p\) and \(V\) always decreases.
Reason : In adiabatic expansion process, work is done by the gas at the cost of internal energy of gas.

Assertion : It is hotter over the top of a fire than at the same distance on the sides.
Reason : In the upward direction, the heat propagate through convection.

One mole of an ideal diatomic gas undergoes
transition from A to B along a path AB as
shown below.

The change in internal energy of the gas
during the transition is

The coefficient of cubical expansion of mercury is \(0.00018 /{ }^{\circ} \mathrm{C}\) and that of brass \(0.00006 /{ }^{\circ} \mathrm{C}\). If a barometer having a brass scale were to read \(74.5 \mathrm{~cm}\) at $$30^{\circ} \mathrm{C}$...