#### vitamin D

##### Active Member

is it just the phenomena when a magnet is moved in and around a coil, an electric current will be generated in the coil ? anything else ?

#### InteGrand

##### Well-Known Member

is it just the phenomena when a magnet is moved in and around a coil, an electric current will be generated in the coil ? anything else ?
Faraday's Law essentially states that an electromotive force will be induced in a loop of wire when it is exposed to a magnetic field that varies with time (so that the flux through the coil varies with time). Mathematically, the law states that the magnitude of this force is equal in magnitude to the rate of change of the flux.

Lenz's Law tells us that the direction of the EMF that is induced is such that the magnetic field from the resultant induced current opposes the changing flux from the external changing magnetic field.

Mathematically, the Faraday and Lenz laws are combined in the equation $\bg_white \varepsilon = -\frac{\mathrm{d}\Phi}{\mathrm{d}t}$ (this is the mathematical expression of the Faraday-Lenz Law). The negative sign is due to Lenz's Law. ($\bg_white \varepsilon$ is the induced emf, $\bg_white \Phi$ is the magnetic flux through the coil and $\bg_white t$ is time.)

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#### keepLooking

##### Active Member
I'm not sure why I laughed more than I should have.

#### Speed6

##### Retired '16
I'm not sure why I laughed more than I should have.

#### sy37

##### Active Member
Faraday's law is simple. Imagine a guitar ok? How do you produce sound? You simply do the thing to the strings with your fingers, kind of like your "cutting them". Well, the strings are now magnetic field lines, and your guitar just disappeared. BOOM. science, bitch. OK. Like the guitar analogy, to induce current ("sound") you need to cut the flux ('guitar lines') because you know, if you just kind of not touch them then nothing will happen. Like, it just won't. You need to keep cutting the flux to produce electromotive force!