7.2 Electomagnetism Flashcards
When a current flows through a wire what happens ?
A magnetic field is created around the wire
What is the field made up of ?
Concentric circles perpendicular to the wire that is carrying the current
What happens if you place a compass next to a wire that is carrying the current ?
As you move a compass it will trace the direction of the magnetic field
What is the right hand thumb rule used for ?
Working out the direction of the magnetic field
How do you use the right hand thumb rule ?
Using your right hand and point thumb in direction of current and curl your fingers. The direction of your fingers is the direction of the field
The larger the current or closer the wire you are the …
The stronger the magnetic field
How do you increase the strength of the magnetic field ?
By wrapping the wire into a coil called a solenoid
Why does the the strength of the magnetic field strength increase with a solenoid ?
Field lines around each loop of wire line up with each other and result in field lines pointing in the same direction that are very close ( closer the lines the strong it is)
Describe magnetic field inside a solenoid ?
Strong and uniform
Magnetic field outside the coil
Just like the one around a bar magnet
What do the ends of the solenoid act like ?
The north and South Pole
How do you increase the field strength of the solenoid ?
By putting a block of iron in the centre of coil and the iron becomes an induced magnet
What happens if you stop the current ?
The magnetic field strength disappears
What is an electromagnet?
A magnet whose magnetic field can be turned on and off with an electric current
