Term
| ElectroMotive Force (emf) |
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Definition
| Pottential difference resulting from a conductor moving through a magnetic field is referred to as emf. |
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Term
Induced emf/current
How is it induced?
Definition,
& unit |
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Definition
Emf is induced(produced) in a wire if there is a relative motion between the wire and a magnetic field. Which can happen:
1. If the wire/coil moves
2. if the magnet or electromagnet moves
3. if the electromagnet is switched on or off or is alternating.
Definition: The induced emf is the amount of mechanical energy converted into electrical energy per unit charge.
Unit: Volt
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Term
Magnetic Flux Φ
Definition
what affects it?
when is it maximum? |
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Definition
Measure of the amount of field lines passing through an area, at right angles to the area.
Can be changed by area or flux density (field strength).
It is maximum when field lines are at right angles to area. |
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Term
Magnetic Flux Φ formula
unit |
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Definition
B=magnetic field strength -(T-tesla)
Θ=angle between flux and line normal to area.
Φ=BAcosΘ
Unit: The weber(Wb)
1 Wb=1Tm2 |
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Term
Magnetic Flux Linkage
definiton + equation
what affects it?
unit |
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Definition
Measure of the number of turns of wire "linked" (passing through) magnetic flux.
N×Φ
Can be increased by:
1. increasing magnetic flux.
2. number of turns of wire.
Same as magnetic flux, Wb, or Tm2
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Term
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Definition
The induced emf(ε) in a circuit is equal to the rate of change of flux linkage through the circuit. (The potential difference produced is eqaul to the rate of which the number of turns of wire passing through an area of field lines )
ε=-Δ(NΦ) |
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Term
Induced ε in a straight conductor moving through a uniform magnetic field.
Deriviation of formula |
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Definition
Since:Φ=BAcosΘ
ε=Δ(Φ)/Δt=Δ(BA)/Δt
Since: B is constant
=B(ΔA/Δt)
Since:A=L×d (d=distance moved)
ε=B(ΔLd/Δt)
Since: L is constant
ε=BL(Δd/Δt)
Since Δd/Δt=velocity
ε=BLv
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