please answering this question step by step as soon as possible. temperature of

Question

please answering this question step by step
as soon as possible.

temperature of 125 F? Estimate the rate of heat loss due to radiation from a covered pot of water at 95°C. How does this compare with the 60 W lost due only to convection and conduction losses? What amount of energy input would be needed to maintain the water at its boiling point for 30 minutes? The polished stainless steel pot is cylindrical, 20 cm in diameter and 14 cm high with a tight-fitting flat cover. The air temperature in the kitchen is about 25°C. State any assumptions you make in making your estimates.

Explanation / Answer

given, T1 = 95 C = 95 + 273 = 368 K

T2 = 25 C = 25 + 273 = 298 K

surface area of the pot, A = 2*pi*r^2 + 2*pi*r*h

= 2*pi*0.1^2 + 2*pi*0.1*0.14

= 0.1508 m^2

rate of energy loss by pot due toradiation, dQ/dt = e*A*sigma*(T1^4 - T2^4)

= 1*0.1508*5.67*10^-8*(368^4 - 298^4) (here we are assuming e(emmisivity) = 1)

= 89.4 W

so, rate of loss of energy due to radiation > rate of loss of energy due to convection and conduction.

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