Faraday's law 333
16
Submitted by : Submitted by : Juhee Mehta Juhee Mehta Class XII Science Class XII Science Submitted to : Submitted to : (Dr.) Mrs. Dheera (Dr.) Mrs. Dheera Samar Samar
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Transcript of Faraday's law 333
Submitted by : Submitted by :
Juhee MehtaJuhee MehtaClass XII ScienceClass XII Science
Submitted to : Submitted to :
(Dr.) Mrs. Dheera Samar(Dr.) Mrs. Dheera Samar
Electromagnetic InductionMagnetic Flux
surface
AdB
surfaceover constant Bif
coscos
AB
AdBAdBAdBsurface
dAB
surface
dAB
surface
If B is constant
Electromagnetic Induction
surface
AdB
Electromagnetic Induction
surface
AdB
surface
dAB AdB
cos
bdxx
Iac
c
2
0
ac
c x
dxIb
20
Faraday’s Law Last time we ended class by dropping a magnet
through a coil. Let’s do it again.
coil
Electromagnetic Induction
Faraday’s Law This phenomena is called electromagnetic induction
and is described by Faraday’s law. Write Faraday’s law.
In order to understand Faraday’s law we need to understand the concept of magnetic flux. Write the definition of magnetic flux.
m
B d
A
Electromagnetic Induction
dt
tdt
)()(
Faraday’s Law The magnetic flux is exactly like the electric flux we
studied in Gauss’s law. The flux is defined in terms of a vector area dA. Describe the magnitude and direction of this vector.
Electromagnetic Induction
normal to area
dA
The magnitude is the common area and the direction is normal to the area.
Electromagnetic InductionFaraday’s Law
Faraday’s Law
Electromagnetic Induction
Does it make a difference if it is the magnetic moving or the coil? This was a major point in Einstein’s theory of relativity.
Electromagnetic InductionFaraday’s Law What about these two cases?
Electromagnetic InductionFaraday’s Law
Faraday’s Law Show that when you integrate the emf, with respect
to time you get the average change in flux in time t.
ttdttd mmm )()(
Electromagnetic Induction
dt
tdt
)()(
Average value
12
2
1
)(
)(tt
dtt
tf
t
t
Example: Induction stove The pan on the stove is heated by eddy currents
produced by induction.
Electromagnetic Induction
Would this stove work with a ceramic bowl?
Does the surface of the stove get hot?
Application of Faraday’s Law Generator
Electromagnetic Induction
Application of Faraday’s Law Magnetic Recording
Electromagnetic Induction
Electromagnetic Induction
Two types of electric fields. One is created by charge and the other is created by a changing magnetic field.
The Most Important Point of Faraday’s Law
A changing magnetic field produces
or creates an electric field.
![PHY204 Lecture 28 - phys.uri.eduPHY204 Lecture 28 [rln28] Magnetic ux and Faraday's law Magnetic eld ~ B (given) Surface S with perimeter loop (given) Surface area A (given) Area vector](https://static.fdocument.org/doc/165x107/600963b4d6e3e50bea657201/phy204-lecture-28-physuri-phy204-lecture-28-rln28-magnetic-ux-and-faradays.jpg)
