Thermodynamics practice · Mixed difficulty

Assertion: When a bullet is fired from a gun, the bullet pierces a wooden block and stops, decreasing the temperature of the bullet and the surrounding layers of wood.
Reason: Temperature is related to the energy of motion of the bullet as a whole.

In an adiabatic process, the quantity which remains constant is

Assertion: In a thermo flask, inner surface is shiny.
Reason: Shiny surface is poor radiator of heat.

Which property of the system does not change in an adiabatic process

(A): If an ideal gas expands in vaccum in an insulated chamber, $\Delta Q, \Delta U, \Delta W$ all are zero.
(R): Temperature of gas remains constant.

In the equation for I law of thermodynamics $d Q=d u+d w$

a) $dQ$ depends on path

b) $dw$ depends on path

c) $du$ depends on path

Two Carnot engines $A$ and $B$ are operated in succession. The first one,$A$ receives heat from a source at ${T_1} = 800K$ and rejects to sink at ${T_2}K$ . The second engine $B$ receives heat rejected by the first engine and rejects to another sink at ${T_3} = 300K$. If the work outputs of two engines are equal, then the value of ${T_2}$ is

For an engine operating between ${t_1}^ \circ C$ and ${t_2}^ \circ C$, the efficiency will be

$100 \mathrm{~mol}$ 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?

An ideal heat engine exhausting heat at ${27^ \circ }C$ is to have 25% efficiency. It must take heat at

Which is the correct statement

If the door of a refrigerator is kept open, then which of the following is true

Which of the following the scalar quantity is

Which of the following process is reversible?

The quantity of heat required to raise one mole through one degree kelvin for a monoatomic gas at constant volume is

A rigid diatomic ideal gas undergoes an adiabatic process at room temperature. The relation between temperature and volume for this process is $T{V^x} =$ constant, then $x$ is

A certain mass of gas at $273K$ is expanded to 81 times its volume under adiabatic condition. If $\gamma = 1.25$ for the gas, then its final temperature is

A hypothetical gas expands adiabatically such that its volume changes from 08 litres to 27 litres. If the ratio of final pressure of the gas to initial pressure of the gas is $\frac{16}{81}$. Then the ratio of $\frac{C_{p}}{C_{v}}$ will be

(A): Heat flows always from a hotter body to a colder body by itself.
(R): Without an external aid heat cannot flow from colder body to a hotter body.

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

A carnot engine takes 300 calories of heat from a source of 500 K and rejects 150 calories of heat to the sink. The temperature of the sink is

A system is taken from a given initial state to a given final state along various paths represented on a $P-V$ diagram. The quantity that is independent of the path is:

When a small amount of heat $\Delta Q$ is added to an enclosed gas, then increase in internal energy and external work done are related as

Assertion: Between states $\left(\mathrm{P}_1, \mathrm{V}_1, \mathrm{T}_1\right)$ and $\left(\mathrm{P}_2, \mathrm{V}_2, \mathrm{T}_2\right)$, work done in two step process is more than work done in one step process.
Reason: Work done is a path function.

The internal energy of a system remains constant
when it undergoes

(A) a cycle process

(B) an isothermal process

(C) an adiabatic process

(D) any process in which the heat given out by the
system is equal to the work done on the system

Choose the correct statement

In gases of diatomic molecules, the ratio of the two specific heats of gases ${C_P}/{C_V}$ is

The efficiency of a Carnot engine is $60 \%$. If the temperature of source is $127^{\circ} \mathrm{C}$. The sink must be maintained at

The specific heat of a gas in an isothermal process is

In which thermodynamic process, volume remains same?

(A): The adiabatic exponent $\left(\gamma=\frac{C_p}{C_v}\right)$ of adiatomic gas is less than that of a mono atomic gas
(R): The molecules of mono atomic gas more degrees of freedom.