# A system is taken from state $$\text{a}$$ to state $$\text{c}$$ by two paths $$\text {adc}$$ and $$\text {abc}$$ as shown in the figure. The internal energy at $$\text a$$ is $$\mathrm{U}_{\mathrm{a}}=10 \mathrm{~J}$$. Along the path $$\text {adc}$$ the amount of heat absorbed $$\delta Q_1=50 \mathrm{~J}$$ and the work obtained $$\delta W_1=20 \mathrm{~J}$$ whereas along the path $$\text {abc}$$ the heat absorbed $$\delta Q_2=36 \mathrm{~J}$$. The amount of work along the path $$\text {abc}$$ is:         1. $$10$$ J  2. $$12$$ J  3. $$36$$ J  4. $$6$$ J

Subtopic: Â First Law of Thermodynamics |
Â 81%
From NCERT
NEET - 2013
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Which of the following relations does not give the equation of an adiabatic process, where terms have their usual meaning?
1. $$\mathrm{P}^{1-\gamma} \mathrm{T}^\gamma= \text{constant}$$
2. $$\mathrm{PV}^\gamma=\text{ constant }$$
3. $$\mathrm{TV}^{\gamma-1}= \text{constant }$$
4. $$\mathrm{P}^{\gamma} \mathrm{T}^{1-\gamma}= \text{constant}$$
Subtopic: Â Types of Processes |
Â 76%
From NCERT
NEET - 2013
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A monoatomic gas at pressure P1 and volume V1 is compressed adiabatically to 1/8th its original volume. What is the final pressure of the gas?

1. P1

2. 16 P1

3. 32 P1

4. 64 P1

Subtopic: Â Types of Processes |
Â 79%
From NCERT
AIPMT - 2010
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At a pressure of $$2$$ atmospheres, a mass of diatomic gas $$(\gamma = 1.4)$$, is compressed adiabatically, causing its temperature to rise from $$27^{\circ}\mathrm{C}$$ to $$927^{\circ}\mathrm{C}$$. The pressure of the gas in the final state is:
1. 8 atm
2. 28 atm
3. 68.7 atm
4. 256 atm

Subtopic: Â Types of Processes |
Â 62%
From NCERT
AIPMT - 2011
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An ideal gas goes from state $$A$$ to state $$B$$ via three different processes as indicated in the $$(P\text-V)$$ diagram.

If $$Q_1,Q_2,Q_3$$${}_{}$ indicate the heat absorbed by the gas along the three processes and $$\Delta U_1, \Delta U_2, \Delta U_3$$ indicate the change in internal energy along the three processes respectively, then:

 1 $$Q_3>Q_2>Q_1$$ and $$\Delta U_1= \Delta U_2= \Delta U_3$$ 2 $$Q_1=Q_2=Q_3$$  and $$\Delta U_1> \Delta U_2> \Delta U_3$$ 3 $$Q_3>Q_2>Q_1$$  and $$\Delta U_1> \Delta U_2> \Delta U_3$$ 4 $$Q_1>Q_2>Q_3$$  and $$\Delta U_1= \Delta U_2= \Delta U_3$$
Subtopic: Â First Law of Thermodynamics |
Â 79%
From NCERT
AIPMT - 2012
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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 |
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From NCERT
AIPMT - 2006
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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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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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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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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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