# An ideal gas is made to undergo a cycle depicted by the $$(P-V)$$ diagram alongside. If the curved line from $$A$$ to $$B$$ is adiabatic, then:                      1. the efficiency of this cycle is given by unity as no heat is released during the cycle. 2. heat is absorbed in the upper part of the straight-line path and released in the lower. 3. if $$T_1$$ and $$T_2$$ are the maximum and minimum temperatures reached during the cycle, then the efficiency is given by, $$1-\frac{T_2}{T_1}.$$ 4. the cycle can only be carried out in the reverse direction as shown in the figure.

Subtopic:  Cyclic Process |
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In this $$(P-V)$$ diagram below the dashed curved line is adiabatic.

For a process, that is described by a straight line joining two points $$X$$ and $$Y$$ on the adiabat (solid line In the diagram) heat is:
(Consider the variations in temperature from $$X$$ to $$Y$$ along the straight line.)

 1 absorbed throughout from $$X$$ to $$Y.$$ 2 released throughout from $$X$$ to $$Y.$$ 3 absorbed from $$X$$ up to an intermediate point $$Z$$ (not shown In the ﬁgure) and then released from $$Z$$ to $$Y.$$ 4 released from $$X$$ up to an Intermediate point $$Z$$ (not shown in the ﬁgure) and then absorbed from $$Z$$ to $$Y.$$
Subtopic:  Types of Processes |
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An ideal gas is taken reversibly around the cycle $$a\text-b\text-c\text-d\text-a$$ as shown on the $$T$$ (temperature) $$\text-S$$ (entropy) diagram.

The most appropriate representation of the above cycle on a $$U$$ (internal energy) $$\text-V$$ (volume) diagram is:

 1 2 3 4
Subtopic:  Basic Terms |
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A gas expands from $$i$$ to $$f$$ along the three paths indicated. The work done along the three paths denoted by $$W_1, W_2, ~\text{and}~W_3$$ have the relationship:

1. $$W_1<W_2<W_3$$
2. $$W_2<W_1=W_3$$
3. $$W_2<W_1<W_3$$
4. $$W_1>W_2>W_3$$
Subtopic:  Work Done by a Gas |
67%
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Thermodynamic processes are indicated in the following diagram:

Match the following:

 Column-I Column-II P. Process I a. Adiabatic Q. Process II b. Isobaric R. Process III c. Isochoric S. Process IV d. Isothermal

 P Q R S 1. c a d b 2. c d b a 3. d b a c 4. a c d b
Subtopic:  Types of Processes |
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The Carnot cycle (reversible) of gas is represented by a pressure-volume curve as shown. Consider the following statements:

 I. Area ABCD = Work done on the gas II. Area ABCD = Net heat absorbed III. Change in the internal energy in cycle = 0

Which of the statement(s) given above is/are correct?

 1 I only 2 II only 3 II and III 4 I, II and III
Subtopic:  Cyclic Process |
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The figure shows the $$(P\text-V)$$ diagram of an ideal gas undergoing a change of state from $$A$$ to $$B$$. Four different paths $$\mathrm{I, II, III}$$ and $$\mathrm{IV}$$, as shown in the figure, may lead to the same change of state.

 (a) The change in internal energy is the same in cases $$\mathrm{IV}$$ and $$\mathrm{III}$$ but not in cases $$\mathrm{I}$$ and $$\mathrm{II}$$. (b) The change in internal energy is the same in all four cases. (c) Work done is maximum in case $$\mathrm{I}$$. (d) Work done is minimum in case $$\mathrm{II}$$.

Which of the following options contains only correct statements?

 1 (b), (c), (d) 2 (a), (d) 3 (b), (c) 4 (a), (c), (d)
Subtopic:  Work Done by a Gas |
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Match the thermodynamic processes taking place in a system with the correct conditions. In the table, $$\Delta Q$$ is the heat supplied, $$\Delta W$$ is the work done and $$\Delta U$$ is the change in internal energy of the system.

 Process Condition (I) Adiabatic (A) $$\Delta W=0$$ (II) Isothermal (B) $$\Delta Q=0$$ (III) Isochoric (C) $$\Delta U\neq0, \Delta W\neq0,\Delta Q\neq0$$ (IV) Isobaric (D) $$\Delta U=0$$

 1 (I) – (B), (II) – (A), (III) – (D), (IV) – (C) 2 (I) – (A), (II) – (A), (III) – (B), (IV) – (C) 3 (I) – (A), (II) – (B), (III) – (D), (IV) – (D) 4 (I) – (B), (II) – (D), (III) – (A), (IV) – (C)
Subtopic:  Types of Processes |
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Consider the following two statements.

 (A): If heat is added to a system, its temperature must increase. (B): If positive work is done by a system in a thermodynamic process, its volume must increase.

 1 Both A and B are correct. 2 A is correct but B is wrong. 3 B is correct but A is wrong. 4 Both A and B are wrong.
Subtopic:  Work Done by a Gas |
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Figure shows P-T diagram for given mass of an ideal gas for the process A→B. During this process, density of the gas is

1. Decreasing

2. Increasing

3. Constant

4. First decreasing then increasing

Subtopic:  Types of Processes |
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