In an experiment, 2kg of water at 20℃ is heated inside a boiler for 20 minutes. Water is boiled to 100℃ and 1.7kg of water remains after boiling. What is the estimated power of the boiler ?
Ans : 1125W
Step Plz ~ THX
CE level Phy Heat Qu.
2008-03-28 7:01 am
回答 (2)
2008-03-28 7:23 am
✔ 最佳答案
咁即係話有0.3kg的水--->steamSpecific latent heat of vaporization of water:2.26x10^6J/kg
specific heat capacity of water is 4200Jkg^-1℃^-1
2kg 20℃water--->2kg100℃water--->1.7kg100℃water+0.3kg100℃steam
紅箭咀 requires heat(energy):2x4200x(100-20)=672000J
藍箭咀requires heat(energy):0.3x2.26x10^6=678000J
If there is not any heat loss,the total energy supplied by the boiler:672000+678000=1350000J
POWER(w)=ENERGY(J)/TIME(s)
P=E/t
P=1350000/(20x60)
P=1125W
2008-03-28 7:37 am
let X be the power of the boiler,
if no energy loss, energy input = energy output
energy input=X 20x60=1200X
energy output=2x4200x80+0.3x2260000
therefore, 1200x=2x4200x80+0.3x2260000
1200x=1350000
x=1125W
if no energy loss, energy input = energy output
energy input=X 20x60=1200X
energy output=2x4200x80+0.3x2260000
therefore, 1200x=2x4200x80+0.3x2260000
1200x=1350000
x=1125W
收錄日期: 2021-04-29 20:24:19
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080327000051KK04269