When of water at is poured into an insulated cup already containing of water at
PHYSICS · Single correct · AP · Physics 2: Algebra-based · Thermodynamics · Thermodynamics
Problem
When 100g of water at 40∘C is poured into an insulated cup already containing 100g of water at 20∘C, which of the following statements about the subsequent heat exchange is correct?
(a) No net heat is transferred between the two water samples because the insulating cup prevents any heat flow.
(b) The cooler water gains more heat than the warmer water loses because its temperature change is larger.
(c) Both portions of water lose heat until thermal equilibrium is reached at 30∘C.
(d) The heat lost by the warmer water equals the heat gained by the cooler water.