Celsius (°C), Fahrenheit (°F), Kelvin (K) – absolute scale.

Relation: (C/100) = (F–32)/180 = (K–273)/100

K = C + 273.15, C = (5/9)(F–32)

Linear expansion: ΔL = α L₀ ΔT   (α = coefficient of linear expansion)

Area expansion: ΔA = β A₀ ΔT   (β ≈ 2α)

Volume expansion: ΔV = γ V₀ ΔT   (γ ≈ 3α)

Anomalous expansion of water: Water has maximum density at 4°C. Between 0–4°C, it expands on cooling (contracts on heating).

Heat capacity: C = Q/ΔT (J/K)

Specific heat capacity (c): Q = m c ΔT (J/kg·K)

Water equivalent: W = m_cal c_cal (mass of water having same heat capacity).

Principle of calorimetry: Heat lost = Heat gained (in a closed system).

Latent heat of fusion (L_f): solid → liquid. For ice: 3.36 × 10⁵ J/kg (80 cal/g).

Latent heat of vaporization (L_v): liquid → gas. For water: 22.6 × 10⁵ J/kg (540 cal/g).

💡 NEET TIPS & SHORTCUTS

• In calorimetry, always convert temperatures to Kelvin or Celsius consistently.
• For expansion, γ for liquids is given directly (not 3α).
• Radiation: power emitted ∝ T⁴, so even small temperature rise increases radiation significantly.
• In steady state conduction through composite slab, heat current (dQ/dt) is same through each layer.

⚠️ COMMON MISTAKES

• Using linear expansion formula for volume changes without multiplying by 3.
• Forgetting to include latent heat in calorimetry problems.
• Assuming Newton's law of cooling holds for large temperature differences.
• Confusing thermal conductivity with thermal resistance.

Linear expansion: ΔL = α L₀ ΔT

Area expansion: ΔA = β A₀ ΔT, β = 2α

Volume expansion: ΔV = γ V₀ ΔT, γ = 3α

Heat capacity: Q = mcΔT (no phase change)

Latent heat: Q = mL (phase change)

Conduction rate: dQ/dt = kA (ΔT/L)

Stefan-Boltzmann: P = σ A e T⁴