用0.5克的25℃水沸至70℃需要用4分鐘,若要將水
由25℃沸至100℃,需要多久?
0.5克的25℃水用4分鐘沸至70℃,若要升至100℃,需要多久?
2008-01-16 2:46 am
回答 (1)
2008-01-16 4:04 am
✔ 最佳答案
Assume no energy is lost to the surroundings,suppose the power of the heater is P .
By E = Pt and E = mcΔT,
Pt = mcΔT
P(4)(60) = (0.5)(4200)(70-25)
P = 393.75W
Then,
(393.75)( t ) = (0.5)(4200)(100-25)
t = 400s
= 6 min 40s which is the required time
參考: My Phy Knowledge
收錄日期: 2021-04-25 13:27:25
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080115000051KK02798