Physics 3- Electromagnetism

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Define a magnetic field
Where magnetic materials feel a force
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How are magnets fields made?
By magnets or a current through a wire
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Describe the magnetic field of a bar magnet
Circular lines going from North to South, lines closer at each end.
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What can be concluded about the area of a magnetic field where the field lines are closer?
That is where the field is strongest
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Describe the magnetic field of a straight wire with a current going through it
Lines around wire in a anticlockwise direction, getting further apart further from the wire
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What can be deduced from the fact field lines around a wire with a current through it get further apart the further from the wire they are?
The field becomes weaker further from the wire
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What is the direction of the circular field lines around a flat coil?
Clockwise (relating to direction of coil)
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Define a solenoid
Long coil with a field running through it
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Describe the magnetic field of a solenoid
Circular lines from one end of the coil to the other (right to left) with straight lines down the middle
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What do the parallel lines through a solenoid show about the magnetic field?
It has constant strength through the middle of the solenoid
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Define the Motor Effect
Where the magnetic effect of electricity produces movement
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Describe the magnetic field/s produced by a current-carrying wire in the magnetic field of two permanent?
2 magnetic fields on top of eachother, 1 from the permanent magnets, 1 from the electricity flowing through the wire.
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What do these two fields produce?
A force which prompts movement
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How is the size of this force increased?
By increasing the current, magnetic field strength or number of wires in the field
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What kind of movement can the motor effect produce on the wire?
Rotational effect
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How can the direction of the force be predicted in the Motor Effect?
Flemming's LEFT hand rule
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In Flemming's Left hand rule, what does the thumb represent?
The direction of motion
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What, in the Flemming's left hand rule, is the direction of field represented by?
The first finger
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What does the second finger represent?
The current
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Describe the force produced when a current is put through a coil and what does it prompt?
Upwards force on one side, downwards force on the other, the coil turns
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What does a split ring communicator in a motor do?
Ensure the force acts upwards on one side, downwards on the other, continuously in one direction.
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Define Induction
When a metal wire cuts through a magnetic field
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What does a wire cutting through a magnetic field produce?
A voltage across the wire
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what happens if the aforementioned wire is connected to a circuit?
The voltage pushes a current around the circuit, ELECTRICITY IS INDUCED
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Does it matter, in the case of induction, whether it's a magnet inside a coil or a coil inside a magnetic field?
No
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What is the relationship between the output voltage or current and the speed of rotation or number of turns on a generator?
They are proportional
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What happens to this when the magnetic field strength increases?
It increases
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How might one find the direction of the induced current?
Flemming's Right Hand Rule
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What does the circular motion in generators usually produce?
An alternating current/voltage
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What does 'an alternating current/voltage' mean?
They change regularly
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What do most of the circular motions in generators mean?
Output current is constantly changing in size?
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How to transformers induce electricity?
By using a changing magnetic field
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What does a step up/step down transformer do?
Increase/decrease voltage
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Wjhat is the iron core used for in a transformer?
Used as a magnetic material to transfer the magnetic field between coils
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What does the alternating current of the primary coil show about the magnetic field around it?
It's changing
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What induces a voltage in the secondary coil?
Constantly changing field
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What does the voltage size depend on?
The number of turns on the coil
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Other cards in this set

Card 2

Front

How are magnets fields made?

Back

By magnets or a current through a wire

Card 3

Front

Describe the magnetic field of a bar magnet

Back

Preview of the front of card 3

Card 4

Front

What can be concluded about the area of a magnetic field where the field lines are closer?

Back

Preview of the front of card 4

Card 5

Front

Describe the magnetic field of a straight wire with a current going through it

Back

Preview of the front of card 5
View more cards

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