Heat Transfer Formula

Question 1

Energy transferred through conduction (through a bar)

Answer 1

Q = (kAΔT)t / L

where k = thermal conductivity of material, A = cross-sectional area of the bar, t = time, L = length, ΔT = change in temp

Question 2

Energy transferred through radiation

Answer 2

Q = eσT⁴At

where e = emissivity of the object, σ = Stefan-Boltzmann’s constant, T = temperature, A = surface area of the radiating body, t = time of exposure