The document discusses electromagnetic induction and its applications. It covers Faraday's laws of electromagnetic induction, including that an electromotive force (EMF) is induced whenever the magnetic flux through a conductor changes. It also describes how this principle is applied in devices like transformers, generators, induction cooktops, motors, and more. The document aims to explain the basics of electromagnetic induction and how it enables various electrical technologies to function.
5. “Electromagnetic Induction is
the production of voltage or
electromotive force due to a
change in the magnetic field.,
and devices such as electric
motors and generators.”
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6. Electromagnetism.
§ Electromagnetism is a process where a magnetic
field is created by introducing the current in the
conductor. When a conductor is electrically
charged it generates magnetic lines of force of
conductor. For example, if current i.e., positive
charges moving in a wire, it produces the
magnetic field along the wire and the direction of
magnetic lines, and force can be determined
using Right Hand Rule.
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8. Faradays Law…
1. Faraday's first law of electromagnetic induction
2. Faraday's second law of electromagnetic
induction
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9. Ø Faraday's first law state that “ whenever ther is a realtive space or
time variation between magnetic field & set of conductors an emf
will induced in the conductor.”
dɸ/dt ≠ 0 where, ɸ = flux & λ = flux linkage
= Nɸ
we know that e=dλ/dt
so, e = N dɸ/dt
Faraday's first law
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10. Faradays second
law..
Ø Faraday's second law state that “the magnitude of
statically induced emf is equal to the rate of change of
flux.”
Two possibilities of generated emf:-
(1) Relative space variation
(2) Realative time variation
• Basic requirement of faraday's law :-
(1) Magnetic field
(2) Set of conductors
(3) Realtive variation in space or time between magnetic field and set of
conductors
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11. Two type of variations…
1. Relative space variation:
Ø In this process of induction of emf conductors are not stationary. i.e. their position keep changing
w.r.t field.
Ø Emf induced in this process is called dynamically induced Emf.
Ø i.e. generators and motors.
2. Relative time variation :
Ø In this process of induction of emf the magnetic flux density varying with time and set of
conductors are stationary.
B → B(t) (so we call it relative time variation)
ɸ = [ B(t) ] A = ɸ(t) e = dɸ(t)/dt (statically induced emf)
Ø i.e. Transformer.
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12. Statically induced emf..
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Ø let the coil has N no of turns.
Ø flux ɸ is linking with the coil.
Ø Here because emf is statically induced conductors are stationary.
Ø so flux must be a function of time.( change with respect to time).
Ø { here (-ve) sign represent the direction of statically induced emf which can be
found by lenz law}
13. Lenz’s Law.
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ØLenz law state that “direction of statically induced emf is such that the current
due to this emf will flows through a close circuit in such a direction that the flux
produce by this current must oppose the main flux which cause the production
of emf.”
ØSimply we can say that induced emf opposes the cause of induction.
Ø(here (-ve) sign indicates that the induced emf opposes the change of flux)
14. Dynamically induced EMF.
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ØMagnitude of dynamically induced emf is found by ”flux cut rule”.
ØAccording to flux cut rule the magnitude of dynamically induced emf is given by....
Ed = Blv sinθ
where, θ = angle between B &V
l = effective length of conductor
V = linear velocity of conductor
B = Flux density in tesla
ØThe direction of dynamically induced emf
can be found by “Fleming right hand rule”
ØFore fingure = direction of flux.
ØMiddle fingure = direction of induced emf
Øthumb = direction of motion of conductor
15. Type of statically induced
EMF.
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Ø If the time varying flux linked with the coil & and EMF is
induced in the same coil then its called self induced EMF.
17. Mutually induced EMF
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When the flux produced by the one coil linked with
another coil due to which an EMF is induced in that coil is
called mutually induced EMF
19. The operation of transformer mainly works on the principle of mutual inductance
between two circuits linked by a common magnetic flux. A transformer is basically used
for transformation of electrical energy
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Transformer Working…
20. 20
Generators..
§ A dc generator is an electrical machine which converts
mechanical energy into direct current electricity. This
energy conversion is based on the principle of production
of dynamically induced emf.
21. § PlacAccording to Faraday’s laws of electromagnetic induction,
whenever a conductor is placed in a varying
magnetic field (OR a conductor
is moved in a magnetic field), an
emf (electromotive force) gets
induced in the conductor.
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Faradays Electromagnetic
Induction…
