Thermal Conduction, Convection & Radiation
Steady-state conduction (dQ/dt = kA(θ₁ - θ₂)/d), Searle’s bar method, natural and forced convection, blackbody radiation, Stefan-Boltzmann law (P = eσAT⁴), and Wien’s displacement law.
Marking a lesson complete represents finishing your study of the topic; it does not denote tested mastery.
Learning Objectives
- Calculate rate of steady-state heat conduction across single and composite layers.
- Determine thermal conductivity of a good conductor using Searle’s bar apparatus.
- Apply Stefan-Boltzmann and Wien’s displacement laws to blackbody radiation emission.
Core Theory & Concepts
Heat transfer describes the energy flow driven by temperature differences via three fundamental mechanisms: conduction through microscopic collisions and free electrons, convection via bulk fluid circulation, and electromagnetic thermal radiation.
Steady-State Conduction
Rate of heat flow is proportional to cross-sectional area and temperature gradient: dQ/dt = k · A · (θ₁ - θ₂) / d.
Stefan-Boltzmann Law
Total power radiated per unit area is proportional to the fourth power of absolute temperature: P = e · σ · A · T⁴.
Common Misconceptions
Thermal radiation requires an intervening gaseous medium to propagate.
Syllabus Topic Outline
- 1Fourier’s law of heat conduction: dQ/dt = k · A · (Δθ / d)
- 2Searle’s bar apparatus for thermal conductivity of copper
- 3Mechanisms of natural and forced convection
- 4Stefan-Boltzmann law of thermal radiation: P = e · σ · A · T⁴
- 5Wien’s displacement law: λ_max · T = b