Chapter 10 — Thermal Properties of Matter

Chapter 10 of the Class 11 Physics NCERT textbook, "Thermal Properties of Matter", encompasses heat, temperature, thermal expansion, specific heat capacity, calorimetry, change of state, and heat transfer. It explains how heat flows through conduction, convection, and radiation, and covers Newton's law of cooling.

• Heat, temperature, and expansion — Temperature measures hotness while heat is energy transferred due to temperature differences. Most materials expand when heated, with distinct coefficients for linear and volume expansion, linked simply for uniform bodies.
• Specific heat, calorimetry, and change of state — Specific heat capacity sets how much heat changes a body's temperature, and calorimetry tracks heat exchange using heat-lost-equals-heat-gained. During melting or vaporising, temperature holds steady while latent heat supplies the energy for the change.
• Modes of heat transfer — Heat moves by conduction through materials, convection via fluid motion, and radiation across space following the Stefan-Boltzmann law. Newton's law of cooling adds that a body cools faster when its temperature excess is larger.

1. 01Heat is energy transferred between systems due to temperature differences; measured in joules (J), temperature in Kelvin (K)
2. 02Absolute temperature scale: T = tc + 273.15, with 0 K as absolute zero where molecular activity ceases
3. 03Thermal expansion: linear (∆l/l = αl∆T) and volume (∆V/V = αv∆T); relation αv = 3αl applies to uniform expansion
4. 04Specific heat capacity s = (1/m)(∆Q/∆T) determines temperature change when heat is absorbed; water has highest capacity among common substances
5. 05Latent heat (L = Q/m) represents energy for state changes—fusion Lf = 3.33×10⁵ J/kg and vaporization Lv = 22.6×10⁵ J/kg for water
6. 06Heat transfer mechanisms: conduction (H = KA(Tc - Td)/L), convection (fluid motion due to density differences), radiation (H = eσAT⁴)
7. 07Newton's law of cooling: rate of heat loss proportional to temperature excess (−dQ/dt = k(T₂ − T₁)) for small temperature differences