First Lawwork Done In Different Thermodynamic Processes Topic
First Law of Thermodynamics : Work Done In Different Thermodynamic Processes
Isobaric Processes:
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Concepts:
- Work done during isobaric expansion is positive, while work done during isobaric compression is negative.
- The work done is equal to the product of pressure and the change in volume.
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Formula: $$W = -P\Delta V$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.5.1
Isochoric Processes:
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Concepts:
- No work is done during an isochoric process, as the volume remains constant.
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Formula: $$W = 0$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.5.1
Isothermal Processes:
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Concepts:
- Work done during an isothermal expansion is negative, while work done during an isothermal compression is positive.
- The work done is equal to the product of the pressure and the natural logarithm of the change in volume.
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Formula: $$W = -nRT\ln\frac{V_f}{V_i}$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.5.2
Adiabatic Processes:
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Concepts:
- No heat is transferred during an adiabatic process.
- The work done is equal to the negative change in internal energy.
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Formula: $$W = -\Delta U$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.5.3
Reversible and Irreversible Processes:
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Concepts:
- A reversible process is one that can be reversed without leaving any changes in the system or the surroundings.
- An irreversible process is one that cannot be reversed without leaving some changes in the system or the surroundings.
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.6
Cyclic Processes:
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Concepts:
- A cyclic process is one in which the system returns to its initial state after undergoing a series of changes.
- The work done in a cyclic process is equal to the net heat added to the system.
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Formula: $$W = \oint PdV$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.7
Efficiency of Heat Engines:
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Concepts:
- Efficiency of a heat engine is defined as the ratio of the work done by the engine to the heat input.
- Carnot’s theorem states that the most efficient heat engine is a reversible engine operating between the same two temperatures.
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Formula: $$\eta = \frac{W_{net}}{Q_H}$$
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Reference: NCERT Physics Class 12, Chapter 13, Section 13.8