Question

Calculate the energy radiated in one minute by a blackbody of surface area 100 cm² when it is maintained at 227ºC. (Take Stefan’s constant σ = 5.67 × 10^-8 J m^-2 s^-1 K^-4)

Answer 1

Data : t = one minute = 60 s, A = 100 cm² = 100 × 10^-4 m² = 10^-2 m² , T = 273 + 227 = 500 K,

σ = 5.67 × 10^-8 W/m² .K⁴

The energy radiated, Q = σAT⁴ t 

= (5.67 × 10^-8 )(10^-2)(500)⁴ (60) J 

= (5.67)(625)(60)(10^-2)J = 2126 J