初中I.S. - Electricity(3)(過來睇睇啦!!)

用戶112948

2007-03-11 7:01 pm

求求各位,我的功課在明天(mon)就要交啦,幫幫我啦~~

http://hk.geocities.com/cute_maxchangmin/is/0005.jpg

C.More about the electric current in parallel circuit:
1.In branch No.1,do the bulbs have the same brightness?Why?
2.In which branch (No.1 or No.2),the bulb(s) is/are the brighter?Why?
3.What will be the electric current in the main loop if the current in branch No.1 is 0.1A?

回答 (1)

2007-03-11 7:22 pm

✔ 最佳答案

asume the three blubs are same

1. in branch no.1 the two blubs have the same brightness, the two blubs share the supply voltage and divided by two, that mean each blub got the same voltage, and they are connect in series, the two blubs have same current and voltage, so their brightness are same.

2. branch no.2 will be brighter, because it got double the voltage of the blubs in branch no.1.

3. if the current in branch no.1 is 0.1A, in branch no.2 will be 0.2A, because branch no.2 resistance is half of branch no.1. so the total current will be 0.3A.

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