Shortcut Methods
JEE Mains Level:
Shortcut Methods
- Use the cyclic integral of entropy change, ∮ dS = Q/T, to calculate the change in entropy for a reversible process.
- Use the inequality ΔS ≥ Q/T to calculate the change in entropy for an irreversible process.
- Remember that the entropy of a pure crystalline substance at absolute zero is zero.
- Use the fact that the entropy of a system increases with increasing temperature and with increasing disorder to predict the direction of entropy changes.
- Use the T-S diagram to visualize the change in entropy for a given process.
Tricks
- Remember that ∮ dS = 0 for a cyclic process.
- Use the fact that Q/T is the area under the curve on a T-S diagram.
- Use the properties of entropy to simplify calculations.
CBSE Board Level:
Shortcut Methods
- Remember that the entropy of a system is a measure of its disorder.
- Remember that the entropy of a system increases when heat is added to it and decreases when heat is removed from it.
- Remember that the entropy of a pure crystalline substance at absolute zero is zero.
- Remember that the entropy of a system at a given temperature T is maximum when the system is in thermal equilibrium with its surroundings.
- Use the T-S diagram to visualize the change in entropy for a given process.
Tricks
- Think about the disorder of a system to predict the direction of entropy changes.
- Use the properties of entropy to simplify calculations.
