electricity question

👨🏻‍🏫 學術台其他 - 科學

A student

2008-12-04 11:18 pm

An iron is designed to operate at 220V or 110V with constant 1100W. Find the resistance of the heating element when the iron is operating at,

a) 220V
b) 110V

THANKS!!

更新1:

Thank you. 1 more question. Is the power (1100W) all used up by the iron? If not, then do the answers stay the same still?

回答 (2)

Chau

2008-12-05 1:51 am

✔ 最佳答案

a)P=V^2/R
1100=220^2/R
R=44歐姆

b)P=V^2/R
1100=110^2/R
R=11歐姆

c)No,there are some energy loss to the internal energy for example,heat energy loss to the surroundings.The answers is more greater than the real answers used up.

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[匿名]

2008-12-04 11:22 pm

a)P=V2/R
1100=(220*220)/R
R=48400/1100
R=44
The resistance is 44
b)P=V2/R
1100=(110*110)/R
R=12100/1100
R=11
The resistance is 11

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