A sphere of surface area 1.25 m² and emissivity 1.0 is at a temperature of 100.0°C.The rate at which it radiates heat into empty space is closest to A)7.1 W B)0.71 mW C)1.4 kW D)9.9 mW E)3.7 W

Question

Quizplus · Accepted Answer

The rate of heat radiation is given by the Stefan-Boltzmann law: P = εσAT⁴. With ε = 1, σ = 5.67 x 10⁻⁸ W/m²K⁴, A = 1.25 m², and T = 373 K, the calculation gives approximately 1.4 kW.

A Sphere of Surface Area 1