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Electromagnetic Induction(Electric current generated by varying magnetic…
Electromagnetic Induction(Electric current generated by varying magnetic fields)
Proved By Faraday and Henry
Magnet bought near coil
Current produced due to relative motion
Coil with current bought near coil
connected to galvanometer
Current produced due to relative motion
Coil connected to battery and
tapping key kept near coil connected to galvanometer
Current produced due to fluctuating current
Produced due to change in Magnetic flux(ΦB)
ΦB=B.A=BAcostheta Wb
Faradays Law of Induction
emf=-dB/dt volt
Lenz Law
Polarity of induced emf is such that it tends to produce current that opposes change in magnetic flux
Motional Electromotive Force
emf=BLv (where v is velocity of moving conductor L is length of conductor and B is external magnetic field)
Electricity and Magnetism are related
Energy Conservation
Current induced = BLv/R (where R is resistance )
Force on conductor=B^2L^2v/r
Power=B^2L^2v^2/R
dQ=dΦB/R
Eddy Current
Induced due to flux change
Opposes induced current
Used in
Magnetic braking in trains
Electromagnetic Damping
Inductance
(Electric current can be induced in coil due to flux change of another coil)
Self Inductance
Change of flux in single isolated coil
EMF= -LdI/dt (Where L is coefficient of self inductance)
L=u0n^2AL (nL=total number of turns A=area of coil)
Mutual Inductance
Change in flux due to current through
one of the two axial solenoids
EMF=-MdI/dt (Where M is coefficient of mutual inductance)
M=u0n1n2pi r^2 L (where r is radius of smaller solenoid n1,n2 is number of turns per length)
AC Generator
Coil rotated due to external force in magnetic field generates current in coil.
Generated Emf= NBA w(sinwt)
Emf,current max at 90 and 270 degrees