Question

A thin, square metal plate measures 14 cm on each side and has emissivity of 0.60. The plate is heated to a temperature of 745°C. What is the rate at which the plate radiates energy ? The Stefan-Boltzmann constant is 5.67 × 10-8 W/(m2 ? K4). Remember that the plate will radiate energy from both its top and bottom surfaces.

Answer 1

L = 15cm = 0.15m

A = 0.15 × 0.15 = 0.0225

Sradiation is transfered from bottom

σ = 5.67 × 10⁻⁸ W/m²k

T = 605 c = 878k

Rate of energy transfer

Q = σ × A × E × T⁴

5.67 × 10⁻⁸ × 0.0225 × 2 × 0.8 × 878⁴

1792.17 W