# Physics 3- Electromagnetism

HideShow resource information
Define a magnetic field
Where magnetic materials feel a force
1 of 37
How are magnets fields made?
By magnets or a current through a wire
2 of 37
Describe the magnetic field of a bar magnet
Circular lines going from North to South, lines closer at each end.
3 of 37
What can be concluded about the area of a magnetic field where the field lines are closer?
That is where the field is strongest
4 of 37
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
5 of 37
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
6 of 37
What is the direction of the circular field lines around a flat coil?
Clockwise (relating to direction of coil)
7 of 37
Define a solenoid
Long coil with a field running through it
8 of 37
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
9 of 37
What do the parallel lines through a solenoid show about the magnetic field?
It has constant strength through the middle of the solenoid
10 of 37
Define the Motor Effect
Where the magnetic effect of electricity produces movement
11 of 37
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.
12 of 37
What do these two fields produce?
A force which prompts movement
13 of 37
How is the size of this force increased?
By increasing the current, magnetic field strength or number of wires in the field
14 of 37
What kind of movement can the motor effect produce on the wire?
Rotational effect
15 of 37
How can the direction of the force be predicted in the Motor Effect?
Flemming's LEFT hand rule
16 of 37
In Flemming's Left hand rule, what does the thumb represent?
The direction of motion
17 of 37
What, in the Flemming's left hand rule, is the direction of field represented by?
The first finger
18 of 37
What does the second finger represent?
The current
19 of 37
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
20 of 37
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.
21 of 37
Define Induction
When a metal wire cuts through a magnetic field
22 of 37
What does a wire cutting through a magnetic field produce?
A voltage across the wire
23 of 37
what happens if the aforementioned wire is connected to a circuit?
The voltage pushes a current around the circuit, ELECTRICITY IS INDUCED
24 of 37
Does it matter, in the case of induction, whether it's a magnet inside a coil or a coil inside a magnetic field?
No
25 of 37
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
26 of 37
What happens to this when the magnetic field strength increases?
It increases
27 of 37
How might one find the direction of the induced current?
Flemming's Right Hand Rule
28 of 37
What does the circular motion in generators usually produce?
An alternating current/voltage
29 of 37
What does 'an alternating current/voltage' mean?
They change regularly
30 of 37
What do most of the circular motions in generators mean?
Output current is constantly changing in size?
31 of 37
How to transformers induce electricity?
By using a changing magnetic field
32 of 37
What does a step up/step down transformer do?
Increase/decrease voltage
33 of 37
Wjhat is the iron core used for in a transformer?
Used as a magnetic material to transfer the magnetic field between coils
34 of 37
What does the alternating current of the primary coil show about the magnetic field around it?
It's changing
35 of 37
What induces a voltage in the secondary coil?
Constantly changing field
36 of 37
What does the voltage size depend on?
The number of turns on the coil
37 of 37

## 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

### Card 4

#### Front

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

### Card 5

#### Front

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

## Comments

No comments have yet been made

## Similar Physics resources:

See all Physics resources »See all Electromagnetism resources »