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final answer is 316 K & 325 k Electronic components are often mounted with good

ID: 1849596 • Letter: F

Question


final answer is 316 K & 325 k

Electronic components are often mounted with good heat conduction paths to a finned aluminum base plate, which is exposed to a stream of cooling air from a fan. The sum of the mass times specific heat products for a base plate and components is 5000 J/K, and the effective heat transfer coefficient times surface area product is 10 W/K. The initial temperature of the plate and the cooling air temperature are 295 K when 300 W of power are switched on. Find the plate temperature after 10 minutes. Find the steady temperature of the components.

Explanation / Answer

a) total heat supplied = change in temp + heat loss

W x t = mcT + hAT

300 x 10 x 60 = 5000(T - 295) + 10(T - 295) x 10 x 60

T = 311.363 K

b)at steady state, total heat supplied is equal to total energy loss

W = hAT

300 = 10(T - 295)

T = 325 K