Below is a concise list of key definitions from Chapter 11: Heat and Thermodynamics

Below is a concise list of key definitions from Chapter 11: Heat and Thermodynamics of the 11th Class Physics syllabus for the Federal Board of Intermediate and Secondary Education (FBISE), aligned with the National Book Foundation (NBF) curriculum. These definitions cover the essential concepts related to heat and thermodynamics as presented in this chapter.

1. Heat: A form of energy transferred between objects or systems due to a temperature difference, measured in joules (J).
2. Temperature: A measure of the average kinetic energy of particles in a substance, typically measured in kelvin (K) or Celsius (°C).
3. Thermodynamics: The branch of physics that studies the relationships between heat, work, and energy.
4. Thermal Equilibrium: The state in which two objects in contact have the same temperature, with no net heat transfer between them.
5. Internal Energy (U): The total energy of a system’s particles, including kinetic and potential energies, due to their random motion and interactions.
6. Specific Heat Capacity (c): The amount of heat required to raise the temperature of 1 kg of a substance by 1 K, given by Q = mcΔT, measured in J/(kg·K).
7. Molar Specific Heat Capacity: The amount of heat required to raise the temperature of 1 mole of a substance by 1 K, measured in J/(mol·K).
8. Latent Heat: The heat absorbed or released during a phase change (e.g., melting, boiling) without a change in temperature.
9. Specific Latent Heat of Fusion (L_f): The heat required to change 1 kg of a solid to liquid at its melting point, given by Q = mL_f, measured in J/kg.
10. Specific Latent Heat of Vaporization (L_v): The heat required to change 1 kg of a liquid to gas at its boiling point, given by Q = mL_v, measured in J/kg.
11. First Law of Thermodynamics: The change in a system’s internal energy equals the heat added minus the work done by the system, expressed as ΔU = Q - W.
12. Work (W): In thermodynamics, the energy transferred when a system changes volume against external pressure, given by W = PΔV, where P is pressure and ΔV is the change in volume.
13. Isothermal Process: A thermodynamic process where temperature remains constant, so ΔU = 0 and Q = W.
14. Adiabatic Process: A thermodynamic process where no heat is exchanged with the surroundings, so Q = 0 and ΔU = -W.
15. Isobaric Process: A thermodynamic process where pressure remains constant.
16. Isochoric Process: A thermodynamic process where volume remains constant, so W = 0 and ΔU = Q.
17. Second Law of Thermodynamics: Heat cannot spontaneously flow from a colder body to a hotter body; the entropy of an isolated system always increases or remains constant.
18. Entropy (S): A measure of a system’s disorder or randomness, with changes given by ΔS = Q/T for reversible processes, measured in J/K.
19. Reversible Process: A theoretical thermodynamic process that can be reversed without changing the system or surroundings, with no net entropy increase.
20. Irreversible Process: A real-world thermodynamic process that cannot be reversed without changing the system or surroundings, increasing total entropy.
21. Heat Engine: A device that converts heat energy into mechanical work through a cyclic process.
22. Efficiency of a Heat Engine: The ratio of work output to heat input, given by η = W/Q_h = (Q_h - Q_c)/Q_h, where Q_h is heat absorbed and Q_c is heat rejected.
23. Carnot Cycle: An ideal reversible cycle with two isothermal and two adiabatic processes, used to determine the maximum efficiency of a heat engine.
24. Carnot Efficiency: The maximum theoretical efficiency of a heat engine operating between two temperatures, given by η = 1 - (T_c/T_h), where T_c and T_h are the cold and hot reservoir temperatures in kelvin.
25. Refrigerator: A device that transfers heat from a cold reservoir to a hot reservoir, requiring external work.
26. Coefficient of Performance (COP): For a refrigerator, the ratio of heat removed from the cold reservoir to the work input, given by COP = Q_c/W.

These definitions cover the core concepts of heat and thermodynamics from Chapter 11 of the FBISE 11th Class Physics curriculum. If you need further clarification or additional terms, please let me know!