Physics : what is Lenz's law ????? Watch

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illumintai
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#1
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#1
I know it s an opposite to Faraday's Law.

and there is a minus sign in front of faraday's law.

If there is a magnetic induction there is always a Back emf (from lenz's law) But lenz's law is exactly opposite to faraday's law which means they cancel out and there is NO induction. !!! ??


Someone HELP !!!
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iiikewldude
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**** i don't know :rolleyes:

hopefully it won't come up tomorrow
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qqqwwweee
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no it is not an opposite to Faraday's Law
Faraday's Law only describes the magnitude
but Lenz law gives the direction
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illumintai
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(Original post by keisiuho)
no it is not an opposite to Faraday's Law
Faraday's Law only describes the magnitude
but Lenz law gives the direction
Can you give me an example question.
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Bezza
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Lenz's law is basically conservation of energy. It says that the induced emf will cause a current to flow in the direction so that it will oppose the motion which is causing the induced emf.
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qqqwwweee
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(Original post by illumintai)
Can you give me an example question.
Imagine there is a permanent bar magnet with its N pole approaching a coil.
Faraday's Law says that the induced emf is the rate of change of flux linkage but doesnt tell which end of the coil has a higher potential. it is analogous to a battery with known emf but you dont know which end is the positive terminal.

Lenz Law tells you that one of the end has a higher potential such that if the current flows, it tends to oppose the field that causes it.
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elpaw
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lenz's law, in word form, states that an induced current opposes the field producing it.
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