# A thermodynamic system is taken through the cycle $$\mathrm{ABCD}$$ as shown in the figure. Heat rejected by the gas during the cycle is:        1. $$2 {PV}$$ 2. $$4{PV}$$ 3. $$\frac{1}{2}{PV}$$ 4. $$PV$$

Subtopic: Â Cyclic Process |
Â 74%
From NCERT
AIPMT - 2012
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One mole of an ideal gas goes from an initial state $$A$$ to the final state $$B$$ with 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 representing the two processes is:

 1 2 3 4

Subtopic: Â Types of Processes |
Â 81%
From NCERT
AIPMT - 2012
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When $$1$$ kg of ice at $$0^{\circ}$$ C melts into the water at $$0^{\circ}$$ C, the resulting change in its entropy, taking the latent heat of ice to be $$80$$ cal/gm, is:
1. $$8\times 10^4$$ cal/K
2. $$80$$ cal/K
3. $$293$$ cal/K
4. $$273$$ cal/K

Subtopic: Â Second Law of Thermodynamics |
Â 57%
From NCERT
AIPMT - 2011
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During an isothermal expansion, a confined ideal gas does -150 J of work against its surrounding. This implies that:

 1 300 J of heat has been added to the gas. 2 no heat is transferred because the process is isothermal. 3 150 J of heat has been added to the gas. 4 150 J of heat has been removed from the gas.

Subtopic: Â First Law of Thermodynamics |
Â 66%
From NCERT
AIPMT - 2011
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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?

 1 $$\Delta U=-\Delta W$$, in an adiabatic process 2 $$\Delta U=\Delta W$$ , in an isothermal process 3 $$\Delta U=\Delta W$$,  in an adiabatic process 4 $$\Delta U=-\Delta W$$, in an isothermal process
Subtopic: Â First Law of Thermodynamics |
Â 81%
From NCERT
AIPMT - 2010
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The internal energy change in a system that has absorbed $$2$$ kcal of heat and done $$500$$ J of work is:
1. $$8900$$ J
2. $$6400$$ J
3. $$5400$$ J
4. $$7900$$ J

Subtopic: Â First Law of Thermodynamics |
Â 78%
From NCERT
AIPMT - 2009
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In thermodynamic processes which of the following statements is not true?

 1 In an adiabatic process, the system is insulated from the surroundings. 2 In an isochoric process, pressure remains constant. 3 In an isothermal process, the temperature remains constant. 4 In an adiabatic process $$PV^\gamma=\mathrm{constant}.$$

Subtopic: Â Types of Processes |
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From NCERT
AIPMT - 2009
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If $$Q$$, $$E$$, and $$W$$ denote respectively the heat added, the change in internal energy, and the work done in a closed cycle process, then:
1. $$W=0$$
2. $$Q=W=0$$
3. $$E=0$$
4. $$Q=0$$

Subtopic: Â Cyclic Process |
Â 77%
From NCERT
AIPMT - 2008
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A Carnot engine whose sink is at $$300~\mathrm{K}$$ has an efficiency of $$40$$%. By how much should the temperature of the source be increased to increase its efficiency by $$50$$% of its original efficiency?

 1 $$275~\mathrm{K}$$ 2 $$325~\mathrm{K}$$ 3 $$250~\mathrm{K}$$ 4 $$380~\mathrm{K}$$
Subtopic: Â Carnot Engine |
Â 64%
From NCERT
AIPMT - 2006
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The molar specific heat at a constant pressure of an ideal gas is $$\frac{7}{2}R.$$ The ratio of specific heat at constant pressure to that at constant volume is:
1. $$\frac{7}{5}$$
2. $$\frac{8}{7}$$
3. $$\frac{5}{7}$$
4. $$\frac{9}{7}$$

Subtopic: Â Molar Specific Heat |
Â 77%
From NCERT
AIPMT - 2006
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