What amount of heat will need to be transferred to the mercury thermometer when it is heated from room temperature t = 20 degrees to the body temperature of a healthy person (36.6)? Consider the mass of mercury equal to m = 2g. Will this amount of heat be equal to the amount of heat received by the thermometer during the temperature measurement?
t1 = 20 ° C.
t2 = 36.6 ° C.
m = 2 g = 2 * 10 ^ -3 kg.
C = 120 J / kg * ° C.
The amount of thermal energy that goes into heating the mercury is determined by the formula: Q = C * m * (t2 – t1), where C is the specific heat of mercury, m is the mass of mercury, t2, t1 are the final and initial temperatures of mercury.
Q = 120 J / kg * ° C * 2 * 10 ^ -3 kg * (36.6 ° C – 20 ° C) = 3.984 J.
The thermometer received more heat from the body than was used to heat the mercury. Part of the heat was used to heat the thermometer itself.
Answer: it took Q = 3.984 J of thermal energy to heat the mercury.
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