Question

A 100 g piece of granite and a 100 g piece of lead are placed in an oven that is at 100°C. The initial temperature of the pieces are 25°C. After a couple of minutes, neither one is at 100°C, but which one is warmer? Which one will reach 100°C first? How much energy will it take for both of the objects to reach 100°C?

Answer 1

specific heat capacity of lead is 0.128 J/goC

specific heat capacity of granite is 0.790 J/goC

Since the specific heat capacity of granite is more than that of the lead , lead requires smaller amount of energy(heat) so it warms first & reaches to 100oC early.

The amount of heat required to reach 100oC to lead is , Q = mcdt

Where

m= mass of lead = 100 g

c = specific heat capacity of lead = 0.128 J/goC

dt = change in temperature = 100-25 = 75 oC

Plug the values we get Q = 960 J

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The amount of heat required to reach 100oC to granite is , Q' = m'c'dt '

Where

m'= mass of granite = 100 g

c = specific heat capacity of granite = 0.790 J/goC

dt = change in temperature = 100-25 = 75 oC

Plug the values we get Q = 5925 J