Question

2. Heat flow, temperature changes, and changes of phase You have a furnace (Tfurnace 400° C that effectively provides an infinite heat source. You design a steel rod (k 50.2 W/m K) that can transmit heat from the furnace to need to a pot of water (specific heat, c = 4190 J/kg.K to raise it's temperature to 100° C. Suppose 1 kg of water in the pot, and the water is initially at a temperature that you have m 10° C Twater,i (a) If you need to start boiling the water in less than 5 minutes, on average, how much heat do you need to transfer per second? (b) In order to achieve this heat current instantaneously, what diameter steel rod do you need if the furnace is 2 m away from the pot of water? (c) If you want to heat the water faster with the same furnace, should you decrease the length of the rod or the diameter? Use the initial temperature as the average of 100° C and 10° C (i.e. 55° C).

Answer 1

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