A Sphere of Surface Area 1

Multiple Choice

A sphere of surface area 1.25 m² and emissivity 1.0 is at a temperature of 100°C.At what rate does it radiate heat into empty space? (σ = 5.67 × 10^-8 W/m² ∙ K⁴)

A) 7.1 W
B) 0.71 mW
C) 1.4 kW
D) 9.9 mW
E) 3.7 W