Electromagnetic Induction

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Qualitatively state Faraday's Law.
The change in a magnetic environment surrounding a coil of wire will cause an EMF to be produced.
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What does the negative sign in Faraday's Law represent?
Lenz's Law.
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Why is the negative sign in Faraday's Law significant?
It enhances Faraday's Law, adding to it that any induced EMF will act to oppose the change that caused it. Mathematically, this is represented by the negative sign.
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In Faraday's Law, what do the terms 'Nϕ' represent?
The term N represents the number of coils in the wire; the term ϕ represents magnetic flux (B x A). When multiplied, they represent 'flux linkage'.
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Explain the 'Corkscrew' effect in relation to a wire carrying an electrical current.
The corkscrew model predicts which way the magnetic field around a wire will orientate itself if that wire carries a current; If the wire is travelling away, the field is clockwise. Converse is true.
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If two wires carrying a current in the same direction are parallel, what happens? Why does this happen?
The field lines intersect causing a force to act between the two wires, pulling them towards one another.
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State the difference between: Magnetic Flux Density, Magnetic Flux, Flux Linkage
A) Magnetic flux density is a synonym for magnetic field strength, it is simply the MFS at a point in the field. B) Magnetic flux is the MFS across a cross-sectional area C) Flux Linkage is magnetic flux across a coil of wire.
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What is the unit of: A) Magnetic Flux Density? B) Magnetic Flux?
A) Symbol B, Unit Tesla (T), Base Units:kgs-2A-1 B) Symbol Φ, Unit Webber (Wb), Base Units: kg m2 s-2 A-1
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Explain Fleming's Left Hand Rule.
Fleming's Left Hand Rule allows you to predict which way a force will act on a wire carrying a current, in a magnetic field. When perpendicular to one another, the thumb, index finger and middle finger represent 'F', 'B' and 'I' respectively.
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How does a basic EM motor work?
A motor contains an axel carrying an electrical current that is allowed to rotate. When placed in an magnetic field, it begins to rotate (predicted by FLHR).
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What equation predicts the force on a current-carrying wire in a magnetic field?
F = BILsinθ (recall sin90 = 1) - L is the length of wire IN the magnetic field.
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What equation could you use to predict the force exerted on a charge travelling through a magnetic field?
F = Bqv (provided it is perpendicular to the field)
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What is conventional current?
Conventional current (incorrectly) assumes that charge flows out of the positive and towards the negative terminals (alternatively from positive to negative sources).
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Flemings Left Hand Rule could be used to predict the deflection of a proton in a magnetic field, true or false?
True.
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Magnetic/electric fields are vector quantities, true or false?
True. They have direction, therefore they are vector quantities.
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Other cards in this set

Card 2

Front

What does the negative sign in Faraday's Law represent?

Back

Lenz's Law.

Card 3

Front

Why is the negative sign in Faraday's Law significant?

Back

Preview of the front of card 3

Card 4

Front

In Faraday's Law, what do the terms 'Nϕ' represent?

Back

Preview of the front of card 4

Card 5

Front

Explain the 'Corkscrew' effect in relation to a wire carrying an electrical current.

Back

Preview of the front of card 5
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