上圖,開關閉合後,伏特機讀數會否改變?解釋!(安培機電阻忽略)
提示:A1讀數增加,A2不變
更新1:
其實呢條題本來係MC, 咁如果做呢類mc時,題目唔指名忽略電池內阻,就要計埋????
F5~physics電路
2009-10-25 9:18 pm
http://farm3.static.flickr.com/2461/4041175477_e5270ba234_o.jpg
上圖,開關閉合後,伏特機讀數會否改變?解釋!(安培機電阻忽略)
提示:A1讀數增加,A2不變
上圖,開關閉合後,伏特機讀數會否改變?解釋!(安培機電阻忽略)
提示:A1讀數增加,A2不變
回答 (3)
2009-10-25 9:59 pm
理論上不變，但實際上有可能會減少，其他電阻可以忽略，但電池內阻冇話唔計，你提示a1增加，增加嘅電流乘電池內阻就係電池減少嘅電壓差。
2009-10-25 9:45 pm
When the circuit is not closed, A1 and A2 are in series so their readings are the same.
When the circuit is closed, the current through the branchs with light bulbs is relatively lower than the current of the main loop, as they are in parallel circuit. THE sum of current of the main loop must be the current of the branches added up.
However those voltage is not affected by those calculaion current so the voltage's is not change.
When the circuit is closed, the current through the branchs with light bulbs is relatively lower than the current of the main loop, as they are in parallel circuit. THE sum of current of the main loop must be the current of the branches added up.
However those voltage is not affected by those calculaion current so the voltage's is not change.
參考: myself
2009-10-25 9:37 pm
Assume all meters are ideal. The reading on the voltmeter will not change.
Reason: the voltmeter is connected to the two terminals of the battery. It thus gives the terminal voltage of the battery, which is unchanged disregard whether the switch is closed or open.
Reason: the voltmeter is connected to the two terminals of the battery. It thus gives the terminal voltage of the battery, which is unchanged disregard whether the switch is closed or open.
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091025000051KK00703