Question

Calculate rate of heat radiated per unit area from the surface of a furnace at a temperature 2000K, assuming it to be a ***** body. If the emissivity is 0.37, then what Is the amount of heat radiated per second? G = 5.67 ×10-8Wm-2K-4 .

Answer 1

From Stefan’* law of radiation, the amount of heat radiated per second is E = σT4.

E = 5.67 × 10-8 × (2000)4

= 5.67 × 24 × 104

= 5.67 × 16 × 104

= 9.072 × 105Js-1.

If e is the emissivity of the surface, then the heat radiated per second R1 = eR

= 0.37 × 9.072 × 105

= 3.35 × 105 Js-1.