magnets Flashcards
Where is the field strongest on the diagram
When the lines are closer togetehr
Where is the strongest part of the field
At the poles of the magnet
How do we know the earth has its own magnetic field
If we hold a compass away from any magnets then the needle points in a north to south direction
The earths magnetic field is due to
The earths core
What’s produced when a current flows through a conducting wire
A magnetic field around the wire
How do we prove that there’s a magnetic field around the wire
When the currents turned on a compass needle deflects
What does the strength of the magnetic field depend on
The size of the current
What does a larger current produce
A stronger magnetic field
If the magnetic field is close to the wire then the magnetic field is at its…
Strongest
Further away from the wire the strength of the magnetic field….
Decreases
If the directions if the current changes we can change….
The direction of the magnetic field - reversed the direction of the conventional current
When the currents reversed then a compass placed near the wire will…
Deflect in the opposite direction
How to find the direction of the magnetic field produced by a wire
Right hand grip rule
What’s the right hand grip rule
Thumb points in the direction of the conventional current
Fingers point in the direction of the magnetic field
How to increase the strength if a magnetic field
Coil the wire - make it a solenoid
When the currents turned on what is inside the solenoid
Strong, uniform magnetic field
How to work out the direction of the magnetic field in a solenoid
Use the right hand grip rule
How does the right hand grip rule work for solenoids
Fingers curl in the same direction as the conventional current
Thumb points in direction of North Pole
How to increase fhe strength of a magnetic field produced by a solenoid
1) increase current size
2) increase the number of turns if the coil
3) place a piece of iron in the solenoid - iron core
What’s an electromagnet
A solenoid with an iron core inside it
Why are electromagnets useful
We can change the strength of the magnetic field by changing the size of the current
Electromagnets can be turned….
On or off
