1.The power of a heater is 150W.It is immersed into 3kg of water at 20°C for
6 minutes.(Specific heat capacity of water = 4200Jkg-1°C-1).Find the
final temperature of water
2. 5kg of hot water at 80°C is poured into 3kg of cold at 0°C. The specific heat
capacity of the water is 4200Jkg-1°C-1.Assume no heat loss to surroundings ,
find final temperature of the mixture
有冇人識做呢2條
唔識做幫下手(phy)物理
2010-04-07 4:02 am
回答 (1)
2010-04-07 4:09 am
✔ 最佳答案
1.By E=P*t=(150*6*60)=54000JBy E=mc(delta T)
54000=3(4200)(T final-20)
so, T final=24.285
2.By E=mc(delta T)
Energy lost by hot water=Energy gain by water
5(4200)(80-T)=3(4200)(T-0)
400-5T=3T
so T=50
參考: myself studying in AL physics
收錄日期: 2021-04-23 22:03:22
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