Mu Physics
Mu Physics
Mu Physics
NO
1. Induction 1
Experiments
2. Faraday’s Law 2
3. Lenz’s Law 4
4. Induced Electric 7
Fields
5. Displacement Current 8
and Maxwell’s
Equation
1. Induction Experiments (Faraday / Henry)
Only a change in the flux through a circuit (not flux itself) can
induce emf. If flux is constant no induced emf.
If the loop is a conductor, an induced current results from emf.
This current produces an additional magnetic field through loop.
From right hand rule, that field is opposite in direction to the
increasing field produced by electromagnet.
3. Lenz’s Law
Magnetic levitation:
-The principle of levitation is Lenz' rule.
3) The induced magnetic field (and the sample) move away from its
cause,
i.e. away from the coil's magnetic field. Then, for a conical coil
(smaller radius at the bottom than at the top) the metallic sample
will move upward
due to this levitation force, until the force of gravity balances the
force of levitation. (The levitation force is larger at the bottom of
the conical coil than at the top of the coil).
Induced Current levitation:
- Problems:
(1) at slow speeds the current induced in the coils of the track’s
conductors and resultant magnetic flux is not large enough to
support the weight of the train. Due to this, the train needs
wheels (or any landing gear) to support itself until it reaches a
speed that can sustain levitation.
(2) this repulsive system creates a field in the track (in front and
behind the lift magnets) which act against the magnets and
creates a “drag force”. This is normally only a problem at low
speed.
-The force that makes the charges move around the loop is not a
magnetic force. There is an induced electric field in the conductor
caused by a changing magnetic flux.
Ampere’s Law