NEET Physics · Flashcards
This deck has 22 flashcards on Thermodynamics for NEET Physics, from NCERT Class 11.
A complete conceptual mastery deck for NEET Thermodynamics, covering the First and Second Laws, state vs. path variables, cyclic process graphs, and Carnot engine efficiencies.
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Card 1 of 22
State the Zeroth Law of Thermodynamics and the physical quantity it defines.
Hint: Temperature is the property that determines thermal equilibrium.
Answer
If two systems are each in thermal equilibrium with a third system, they are in thermal equilibrium with each other. It defines the concept of Temperature.
Card 2 of 22
What is the Internal Energy (U) of a system? On what does it depend for an Ideal Gas?
Hint: U is a STATE variable (depends only on the current state, not the path).
Answer
Internal energy is the sum of macroscopic kinetic and potential energies of the molecules. For an IDEAL GAS, there are no intermolecular forces (so Potential Energy = 0). Thus, U is purely kinetic and depends ONLY on Temperature.
Card 3 of 22
State the First Law of Thermodynamics mathematically.
Hint: This is a statement of the Law of Conservation of Energy.
Answer
ΔQ = ΔU + ΔW (Heat supplied to the system = Change in internal energy + Work done BY the system).
Card 4 of 22
What is the standard Sign Convention for Heat (Q), Work (W), and Internal Energy (U)?
Hint: Expansion = Positive Work. Compression = Negative Work.
Answer
1. +Q: Heat supplied TO the system; -Q: Heat rejected BY the system. 2. +W: Work done BY the system (Expansion); -W: Work done ON the system (Compression). 3. +ΔU: Temperature increases; -ΔU: Temperature decreases.
Card 5 of 22
Define an Isothermal Process and write its equation of state.
Hint: Since ΔT = 0, the change in internal energy (ΔU) is also ZERO for an ideal gas.
Answer
A process in which Temperature remains constant (ΔT = 0). Equation: PV = constant (Boyle's Law).
Card 6 of 22
What does the First Law of Thermodynamics become for an Isothermal Process?
Hint: All heat added is completely converted into work done by the gas.
Answer
Since ΔU = 0 (because temperature is constant), the First Law (ΔQ = ΔU + ΔW) becomes: ΔQ = ΔW
Card 7 of 22
Write the formula for Work Done (W) in an Isothermal Process.
Hint: Requires a perfectly conducting cylinder and a very SLOW process.
Answer
W = nRT ln(V₂ / V₁) = 2.303 nRT log₁₀(V₂ / V₁) Or in terms of pressure: W = nRT ln(P₁ / P₂)
Card 8 of 22
Define an Adiabatic Process and write its equation of state.
Hint: Other relations: TV^(γ-1) = constant, and (T^γ)/(P^(γ-1)) = constant.
Answer
A process in which NO heat is exchanged with the surroundings (ΔQ = 0). Equation: = constant (where γ = / ).
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