Understanding Lenz's Law - Get a Clear Explanation Now

In summary, Lenz's law states that in a given circuit with an induced EMF caused by a change in a magnetic flux, the induced EMF causes a current to flow in the direction that opposes the change in flux.
  • #1
needhelp123
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i am having so much difficulty understanding lenz's law.

i don't know what it means and how to use it.

will someone please give me a good explanation for it because my book SUCKS and I'm having a very hard time understanding this hard(and stupid) topic so please help me.
 
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  • #2
Can you give us one of the examples that your book uses for Lenz's Law and tell us what you don't understand about it? Then perhaps someone can give you an explanation that's more likely to help you, rather than giving a general explanation that might just repeat what you've already seen (and don't understand).
 
  • #3
Lenz's Law states that in a given circuit with an induced EMF caused by a change in a magnetic flux, the induced EMF causes a current to flow in the direction that opposes the change in flux. That is, if a decreasing magnetic flux induces an EMF, the resulting current will oppose a further decrease in magnetic flux. Likewise, for an EMF induced by an increasing magnetic flux, the resulting current flows in a direction that opposes a further increase in magnetic flux.

It is important to note that the induced current will always flow in a direction which opposes any change of magnetic flux, but it does not oppose the magnetic flux itself.

Lenz's law can be derived from Faraday's law of induction, simply by noting the minus sign on the right side of the equation. How Lenz got his name in history for this is beyond me!

Lenz's law states that "direction of induced EMF is opposite to very cause producing it"
In the case of an inductor coil where the electric wire makes N turns, the formula becomes:
e = -N dΦ/dt

where e is the induced electromotive force and dΦ/dt is the time-rate of change of magnetic flux Φ.
 
  • #4
How about this, a loop of wire absolutely hates having its magnetic flux changed. It will do everything it can to try to keep it the same, i.e. induce a current, and thus a magnetic field to replace the old one, or counter the new one. Lenz's law tells you which way to point your thumb to figure out the current direction. If it's losing flux, point your thumb in the direction it was pointing to restore it. If it's gaining flux, point your thumb against it to oppose it.
 
  • #5
people always always have major trouble with lenz' law. I've never really been able to get it myself unless i can figure out the direction of the chane in flux.
often times people can not even understand clockwise and counterclockwise. which admittedly is arbitrary and confusing because it is relative. people understand into the page and out of the page or left and right but CCW and CW are confusing. it depends on how you look at your hands like from which vantage point.
but i do have a question.
why does the wire "hate" having its magnetic flux or flow of direction of current change? I mean why should it care?

this website helped me a lot to learn Lenz Law

http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/MagneticField/LenzLaw.html
 
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Related to Understanding Lenz's Law - Get a Clear Explanation Now

1. What is Lenz's Law?

Lenz's Law is a fundamental law in electromagnetism that states that the direction of an induced current in a conductor will be such that it creates a magnetic field that opposes the change in magnetic flux that caused the current.

2. How does Lenz's Law work?

Lenz's Law is based on the principle of conservation of energy. When there is a change in the magnetic flux through a conductor, it creates an induced current which in turn creates a magnetic field that opposes the change in flux. This opposition to the change in flux results in the conservation of energy.

3. What is the importance of Lenz's Law?

Lenz's Law is important because it helps us understand and predict the behavior of electromagnetic induction. It also plays a crucial role in the design and operation of various electrical devices such as generators, transformers, and motors.

4. How is Lenz's Law related to Faraday's Law?

Lenz's Law is a consequence of Faraday's Law of induction, which states that an electric current is induced in a conductor when it is exposed to a changing magnetic field. Lenz's Law provides a way to determine the direction of the induced current based on the direction of the change in magnetic flux.

5. Can you provide an example of Lenz's Law in action?

One example of Lenz's Law in action is the braking system in a bicycle. When the brake pads come in contact with the wheel, the wheel's rotational motion creates a changing magnetic flux in the metal rim. This change in flux induces a current in the rim, which in turn creates a magnetic field that opposes the motion of the wheel, resulting in the wheel slowing down and eventually stopping.

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