A student performs an experiment to study the law of conservation of
energy. A copper block of mass 0.3 kg is heated to 100'C and then
put into a polystyrene cup which contains 250 ml of water at 25'C.
The temperature of the mixture is 32'C.
a) Find the energy lost by the block
b) Find the energy gained by the water
c) Find the percentage of energy lost by the copper block th the surroundings.
Physical 問題2(+20)
2009-10-03 6:17 am
回答 (1)
2009-10-05 12:03 am
✔ 最佳答案
Specific heat capacity of copper, c = 385 Jkg-1K-1a. Energy lost by the block
= mcT
= (0.3)(385)(100 - 32)
= 7854 J
b. Energy gained by water
= m'c'T'
= (0.250)(4200)(32 - 25)
= 7350 J
c. The percentage of energy lost
= (7854 - 7350) / 7854 X 100%
= 6.42%
參考: Physics king
收錄日期: 2021-04-19 15:56:06
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