The figure below shows two paths that may be taken by gas to go from state $$A$$ to state $$C$$

In process $$AB$$, $$400~\text{J}$$ of heat is added to the system, and in process $$BC$$, $$100~\text{J}$$ of heat is added to the system. The heat absorbed by the system in the process $$AC$$ will be:
1. $$380~\text{J}$$
2. $$500~\text{J}$$
3. $$460~\text{J}$$
4. $$300~\text{J}$$

Subtopic: Â First Law of Thermodynamics |
Â 58%
From NCERT
NEET - 2015
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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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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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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 77%
From NCERT
AIPMT - 2009
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