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To measure the specific heat of copper, a copper lump is heated in an oven and then dropped into a beaker of water. To compute the specific heat, the experimenter must know or measure every quantity below EXCEPT:

1. the heat capacity of the water and beaker
2. the original temperatures of the copper and the water
3. the final (equilibrium) temperature of the copper and the water
4. the time taken to reach equilibrium after the copper is dropped into the water

Correct answer: the time taken to reach equilibrium after the copper is dropped into the water

Solution

The energy balance m_Cu*c_Cu*(T_hot - T_f) = (heat capacity of water+beaker)*(T_f - T_cold) contains no time term, so the time to reach equilibrium is not needed.

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