Kinetic Theory of Gases and Radiation

Gas molecules are point masses, Intermolecular forces are negligible except during collisions, Collisions between molecules are perfectly elastic, Gas molecules are in continuous random motion

The kinetic theory assumes: point masses, negligible intermolecular forces except during collisions, elastic collisions, and continuous random motion. Molecules have a distribution of speeds, not the same speed.

Becomes half

Wien's law states λ_max = b/T. If temperature doubles (2T), then λ_max = b/(2T) = (1/2)(b/T), so wavelength becomes half.

1.04 × 10⁵ Pa

Using P = (1/3)ρv²_rms: P = (1/3) × 1.25 × (500)² = (1/3) × 1.25 × 250000 = 104167 Pa = 1.04 × 10⁵ Pa

Power radiated ∝ T⁴, Stefan constant σ = 5.67 × 10⁻⁸ W/m²K⁴, For ordinary bodies: R = eσT⁴

Stefan-Boltzmann law states R = σT⁴ for blackbodies and R = eσT⁴ for ordinary bodies where e is emissivity. The law shows T⁴ dependence, not T². It applies to all bodies with appropriate emissivity factor.