Why negative sighn in faraday law of electromagnetic induction?

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Discussion Overview

The discussion revolves around the negative sign in Faraday's law of electromagnetic induction, specifically its significance and implications. Participants explore the relationship between the negative sign and Lenz's law, as well as the consequences of hypothetically removing the negative sign from the law.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that the negative sign in Faraday's law represents Lenz's law, which indicates that the induced emf opposes the change that produces it.
  • One participant provides an example where pushing a magnet towards a coil induces a current that creates a magnetic field opposing the magnet's motion.
  • Another participant questions the implications of removing the negative sign from the law, suggesting that it cannot simply be disregarded.
  • Some participants speculate on the consequences of assuming Lenz's law is incorrect, suggesting that it could lead to violations of energy conservation and the emergence of "free" energy sources.
  • There is a mention of a contradiction between the law's predictions and actual observations if Lenz's law were to be disregarded.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the negative sign and Lenz's law, with no consensus on the hypothetical scenario of removing the negative sign or the validity of Lenz's law itself.

Contextual Notes

Some assumptions about the nature of energy conservation and the relationship between induced emf and magnetic fields are not fully explored, leaving room for further discussion.

waqarrashid33
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pleasezzzzzz anyone can clear me on this point:
why -ve sighn comes in faraday law of electro magnetic induction?what is it sighnificance?if in answer value of induce EMF become -ve than what will be its direction.
 
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The minus sign expresses Lenz's law which in turn expresses the conservation of energy..."the induced emf is in a direction such that it opposes the change producing it".As an example if you push a magnet towards a coil on closed circuit the induced current will cause the coil to become magnetised in a direction such that it repels the magnet.The work done in overcoming this repulsion is converted to electrical energy.
 
if the -ve sighn is removed then what will be done with this law?
 
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i mean that if we assume that lenz's law is wrong then what will happen?
 
waqarrashid33 said:
i mean that if we assume that lenz's law is wrong then what will happen?
For one thing, energy will not be conserved--you'll have a source of "free" energy.
 
waqarrashid33 said:
i mean that if we assume that lenz's law is wrong then what will happen?
Then we get a contradiction between what the law says and what is actually observed.
 

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