Heat and Thermodynamics

The ratio of the specific heats \({{{C_p}} \over {{C_v}}} = \gamma\) in terms of degrees of freedom (n) is given by

Two vessels separately contain two ideal gases A and B at the same temperature, the pressure of A being twice that of B. Under such conditions, the density of A is found to be 1.5 times the density of B. The ratio of molecular weight of A a...

An ideal gas is compressed to half its initial volume by means of several processes. Which of the process results in the maximum work done on the gas ?

The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is \(-\)20oC, the temperature of the surroundings to which it rejects heat is

A thermodynamic system undergoes cyclic process ABCDA as shown in figure. The work done by the system in the cycle is

A monatomic gas at a pressure P, having a volume V expands isothermally to a volume 2V and then adiabatically to a volume 16V. The final pressure of the gas is (Take \(\gamma\) = 5/3)

The mean free path of molecules of a gas, (radius r) is inversely proportional to

Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?

A system is taken from state a to state c by two paths adc and abc as shown in the figure. The internal energy at a is \({U_a} = 10\,J\). Along the path adc the amount of heat absorbed dQ1 \(=\) 50 J and the work obtained dW1 \(=\) 20 J whe...

Two Carnot engines A and B are operated in series. The engine A receives heat from the source at temperature T1 and rejects the heat to the sink at temperature T. The second engine B receives the heat at temperature T and rejects to its si...

In a vessel, the gas is at pressure P. If the mass of all the molecules is halved and their speed is doubled, then the resultant pressure will be

A gas is taken through the cycle
A \(\to\) B \(\to\) C \(\to\) A, as shown. what is the net work done by the gas?

In the given (V \(-\) T) diagram, what is the relation between pressure P1 and P2?

The amount of heat energy required to raise the temperature of 1 g of Helium at NTP, from T1K to T2K is

During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of \({{{C_p}} \over {{C_p}}}\) for the gas is

One mole of an ideal gas goes from an initial state A to final state B via two processes : It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P-V diagram...

A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is

An ideal gas goes from state A to state B via three different processes as indicated in the P-V diagram.

If Q1, Q2, Q3 indicate the heat absorbed by the gas along the three processes and \(\Delta\)U1, \(\Delta\)U2, \(\Delta\)U3 indicat...

When 1 kg of ice at 0oC melts to water at 0oC, the resulting change in its entropy, taking latent heat of ice to be 80 cal/oC, is

During an isothermal expansion, a confined ideal gas does \(-\) 150 J of work against its surroundings. This implies that

A mass of diatomic gas \((\gamma = 1.4)\) at a pressure of 2 atmospheres is compressed adiabatically so that its temperature rises from 27oC to 927oC. The pressure of the gas in the final state is

If \(\Delta\)U and \(\Delta\)W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true ?

A monatomic gas at pressure P1 and volume V1 is compressed adiabatically to \({{1 \over 8}^{th}}\) of its original volume. What is the final pressure of the gas?

If cp and cv denote the specific heats (per unit mass of an ideal gas of molecular weight M, then

In thermodynamic processes which of the following statements is not true ?

The internal energy change in a system that has absorbed 2 kcal of heat and done 500 J of work is

If Q, E and W denote respectively the heat added, change in internal energy and the work done in a closed cyclic process, then

At 10oC the value of the density of a fixed mass of an ideal gas divided by it pressure is x. At 110oC this ratio is

An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62oC, its efficiency is doubled. Temperatures of the source is

A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency ?

The molar specific heat at constant pressure of an ideal gas is (7/2) R. The ratio of specific heat at constant pressure to that at constant volume is

Which of the following processes is reversible?

An ideal gas heat engine operates in Carnot cycle between 227oC and 127oC. It absorbs 6 \(\times\) 104 cal of heat at higher temperature. Amount of heat converted to work is

One mole of an ideal gas at an initial temperature of T K does 6R joule of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is 5/3, the final temperature of gas will be

The equation of state for 5 g of oxygen at a pressure P and temperature T, when occupying a volume V, will be
(where R is the gas constant)

An ideal gas heat engine operates in a Carnot cycle between 227oC and 127oC. It absorbs 6 kcal at the height temperature. The amount of heat (in kcal) converted into work is equal to

The efficiency of Carnot engine is 50% and temperature of sink is 500 K. If temperature of source is kept constant and its efficiency raised to 60%, then the required temperature of sink will be

A scientist says that the efficiency of his heat engine which work at source temperature 127oC and sink temperature 27oC is 26%, then

The (W/Q) of a Carnot engine is 1/6, now the temperature of sink is reduced by 62oC, then this ratio becomes twice, therefore the initial temperature of the sink and source are respectively

To find out degree of freedom, the expansion is