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Magnetic Field - Coggle Diagram
Magnetic Field
Magnetic field is a vector field that describe the magnetic influence on moving electric charges, electric currens and magnetic materials.
Demagnetization
The process of reducing or removing the magnetism of a ferromagnetic material. The reduction of magnetic induction by the internal field of a magnet
Terrestrial Magnetism
- The magnetism of the Earth
- A branch of geophysics that deals with the Earth's magnetic condition
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The Bio-Savart Law
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Notice that if dl ad r are parallel, the contribution is zero
Torque on a Current Loop
A current-carrying loop if wire attached to a vertically rotating shaft feels magnetic forces that produce a clockwise torque as viewed from above.
Motors are the most common application of magnetic force on current-carrying wires.
Motors have loops of wire in a magnetic field. When current is passed through the loops, the magnetic field exerts torque on the loops, which rotates a shaft. Electrical energy is converted to mechanical work in the process.
Torque, τ= rF sinθ
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r is the distance from the pivot that the force is applied, and
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Since r=w/2, the torque on each vertical segment is (w/2)Fsinθ
Total Torque, τ=w/2 F sinθ+w/2 F sinθ=wF sinθ
If we have a multiple loop of N turns, and the area of the loop is A=wl, then the expression for the torque becomes τ=NIAB sinθ
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Faraday's Law
Any change in the magnetic environment of a coil of wire will cause a voltage (emf) to be “induced” in the coil. No matter how the charge is produced, the voltage will be generated.
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The induced emf in a coil is equal to the negative of the rate of change of magnetic flux times the number of turns in the coil, N. It involves the interaction of charge with magnetic field.
Lenz's Law
Lenz’s Law of Electromagnetic Induction states that the direction of the current induced in a conductor by a changing magnetic field (as per Faraday’s Law of electromagnetic induction) is such that the magnetic field created by the induced current opposes the initial changing magnetic field which produced it
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