Consider a cylindrical cavity of diameter D = 100 mm and depth L = 50 mm whose sidewall and bottom are diffuse and gray with an emissivity of 0.6 and are at a uniform temperature of 1500 K. The top of the cavity is open and exposed to surroundings that are large and at 300 K.

(a) Calculate the net radiation heat transfer from the cavity, treating the bottom and sidewall of the cavity as one surface (q_A)

(b) Calculate the net radiation heat transfer from the cavity, treating the bottom and sidewall of the cavity as two separate surfaces (q_B)

(c) Plot the percentage difference between q_A and q_B as a function of L over the range 5 mm < L < 100 mm,