cooling curve of 2 metals

2009-11-24 11:50 pm

Find out true or false.
It is the cooling curve of 2 metals of same mass, same initial temp and same environment.
Temp
　 ↑
　　| \＼
　　| \　＼ (2 straight line: Q steeper, P gentler)
　　| \　　＼
　　|　\ Q　＼P
　－|－－－－－－－＞time
(1) Specific heat capacity Q<P. (T/F)
(2) Rate of energy emit Q>P. (T/F)
(3) We feel Q cooler at room temperature. (T/F)

更新1:

(1) Specific heat capacity Q smaller than P. (T/F) (2) Rate of energy emit Q larger than P. (T/F) (3) We feel Q cooler at room temperature. (T/F)

回答 (1)

天同

2009-11-25 4:05 am

✔ 最佳答案

(1) True.
For the same rate of loss of heat to the surroundings, temperature of an object with lower specific heat capacity will decrease faster.

(2) False.
The rate of loss of heat to the surroundings is proportional to the excess temperature (Newton's Law of Cooling). Since the two pieces of metals are of the same initial temperature, their rates of loss of heat are the same.

(3) Can't tell.
The feeling of cold and hot depends on human feeling, and is determined by the thermal conductivity of the metal. Metals with high thermal conductivity will give a cool feeling than metals with low thermal conductivity.

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