Where is the strongest part of the magnetic field created by a bar magnet?
At the poles
What does the Earth's magnetic field protect us from?
Solar winds
Define the motor effect...
A current carrying wire placed in an external magnetic field will experience a force.
Explain the role of the commutator in this motor
The commutator changes the direction of the current when the coil rotates, this keeps the coil going in a circle.
What happens to the strength of the magnetic field created by a current carrying wire as you get further from the wire?
The field gets weaker
Why does a compass needle point north?
The needle is a magnet, the north pole of the needle is attracted to the south pole of the Earth
Give one way you could increase the strength of the magnetic field created by this solenoid.
Increase the current / increase the number of turns / put an iron bar through the middle
A superconductor is a material that when cooled will allow a massive amount of current to flow through it. Why does this MRI machine use superconducting wires for its electromagnet?
A very strong electromagnet requires massive amounts of current.
Which pole of the Earth's magnetic field is at the "North Pole"?
The south pole
A steel paper clip is brought into a magnetic field and attached to the end of a bar magnet. The paperclip now behaves as a magnet, what type of magnetism is this?
Induced magnetism
What will happen to the compass needle if the bar magnet is rotated 180o?
The needle will point the other way
Explain how the motor effect causes this motor to spin
The left hand side of the coil experiences a downward force, the right hand side of the coil experiences an upward force.
Which pole is Y?
South pole (it is attracting the north pole of the compass)
When the activity of the sun is high, charged particles from solar winds can flow along the earth's magnetic field lines and enter the atmosphere near the poles. What visual effect does this create?
The Aurora borealis (northern lights)
What type of magnet allows this scrap crane to pic up and then drop scrap steel?
An electromagnet (these can be turned on and off)
What will happen when the bell switch is closed?
The electromagnet will attracted the iron armature which will ring the bell
If you are looking from above, which direction will the magnetic field created by this wire be going?
Clockwise (use the right hand thumb rule)
Which pole is X?
North
What happens to the distance between magnetic field lines when the field gets stronger?
The field lines get closer together
What will happen to the compass needles when a current flows through the wire?
The needles will line up with the magnetic field created by the current carrying wire