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27 Apr 2012 20:03:21 IST

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series of parallel plate capacitors- how do 1st plate of C1 & last plate acquire charge?

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greetings!

class 12 cbse curriculum.

in the combination of parallel plate capacitors, series arrangement, my student does not understand that when the left most plate (1st plate of 1st capacitor) is attached to the postive terminal of the battery, it gets a charge of +Q, and the right most plate (2nd plate of last capacitor)attached to the negative terminal, gets a charge of -Q. He says that getting a potential is fine, but how does the plate acquire charge? He asked that whether the circuit is complete or not, whether current is flowing or not. if current is not flowing, plate cannot acquire charge.. how do i explain?

Comments (5)

GOPAKUMAR

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Joined: 18 Mar 2010

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27 Apr 2012 20:50:31 IST

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well, intially when uncharged the capacitor behaves as a short circuit and cureent flows through it but once fully charged it behaves as an open circuit and current stops flowing . Thus they get charged and while charging current flows in circuit......

Chandni

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27 Apr 2012 23:13:30 IST

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thank you sir!:)

Krishna Gopal Singh

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28 Apr 2012 04:05:54 IST

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If there is no charge on the plates there will be no potential difference. the potential difference comes only because of charge. Initially when battery is connected there is potential difference across capacitor and all potential difference is across the connecting wire. This causes current to flow through wire and accumulate on plates of capacitor. When the charge on capacitor is sufficient so that potential difference across capacitor is equal to potential difference across battery there is no potential difference across wires and flow of charge stops.

Chandni

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28 Apr 2012 09:56:08 IST

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sir u mean to say that

Initially when battery is connected there is no potential difference across capacitor and all potential difference is across the connecting wire ?? i guess the word "no" is missing in ur post?

Tyler Waddington

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28 Apr 2012 10:53:48 IST

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I might also add that you could have your student look at it in such a way that as the current flows from the battery's positive terminal and across the capacitor, the left most plate acquires a positive charge. This positive charge causes negative charges to attract to it, thus causing a build up of negative charge on the opposite plate. This happens until the capacitor reaches maximum charge and (like the others said) current stops.

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