Magnetism Flashcards
(26 cards)
Describe the features of a bar magnet
A bar magnet has two ends, a north and south pole.
The magnetic forces are strongest at the poles of the magnet
When you bring two magnets close together they exert a ____ on each other
Force
What happens when you bring two like poles together ( + and +)
or (- and -)?
They repel eachother
What happens when you bring two unlike poles together?
They attract each other
The attraction and __________ between two magnetic poles are both examples of ____ -______ _________
Repulsion
Non- contact
A permanent magnet produces its own ________ ____
Magnetic field
What is an induced magnet?
An object that becomes a magnet when it is placed in a magnetic field
What happens if you take away a permanent magnetic from an induced magnetic?
The induced magnet will lose most/all of its magnetism
Name the four types of magnetic material that can be made into a permanent or induced magnet
Iron
Steel
Nickel
Cobalt
What is a magnetic field?
A region around a magnet where a force acts on another magnetic material or a magnet
Would would happen if you placed, for example, iron into a magnetic field?
The iron will experience a force of attraction towards the magnet.
The strength of this magnetic field depends on the distance from the magnet, if its further away there is less attraction.
What happens when a current flows through a conducting wire?
A magnetic field is produced around the wire.
The field is made up of concentric circles, perpendicular to the wire in the centre.
How can you work out the direction of the field using the direction of the current?
Using the right hand thumb rule
Point thumb in the direction of the current and curls fingers, direction of fingers is direction of the field
What is a solenoid?
A long coil of wire
How can you increase the strength of the magnetic field in a current carrying wire?
Add more coils to the wire
Or placing an iron core in the solenoid
When we turn on the current in a solenoid we get a _____ and _______ magnetic field inside the solenoid.
Strong
And uniform
A solenoid is an example of what…?
An electromagnetic
What do transformers do and how do they work?
Transformers use induction to change the size of the potential difference of an ALTERNATING current
Name the two coils of wire on a transformer
Primary (L)
Secondary (R)
Which side has more coils for
A) a step up transformer
B) a step down transformer
A) more coils on secondary coil
B) more coils on the primary coil
The primary and secondary coils are completely ________ and are both wrapped around an ______ core - which is easily ___________
Separate
Iron
Magnetised
Which coil is connected to the alternating current?
Primary
Describe and explain the flow of current and magnetic field in a transformer
As the current flows through the primary coil it generates a changing magnetic field, which is transmitted along the iron core and passes through a secondary coil, this induces a potential difference AND the wire experiences a force.
How do you determine the motion of the force on a current-carrying conductor?
FLEMINGS LEFT HAND RULE:
- place thumb, first finger and second finger so they are at right angles
- First finger= direction of magnetic field from north to south (F -> field
- Second finger = direction of current (seCond -> current)
- Thumb = DIRECTION OF THE MOTION or force ( thuMb -> motion)
