Topic 12 - Magnetism And The Motor Effect Flashcards
(30 cards)
At which part of a magnet are the magnetic forces strongest?
The poles
What type of force is exerted if two like poles of a magnet are brought near each other?
They repel each other
What type of force is exerted if two unlike poles of a magnet are brought near each other?
They attract each other
What is a magnetic field?
The region surrounding a magnet where another magnet or magnetic material experiences a non-contact force
What is the difference between a permanent magnet and an induced magnet?
A permanent magnet produces its own magnetic field
An indices becomes magnetic when placed in a magnetic field
What type of force is always caused by induced magnetism?
Attraction
Give four examples of magnetic materials?
Iron, steel, cobalt, nickel
How does the strength of a magnetic field as you move further away from the magnet?
The strength decreases
In what direction does a magnetic field point?
From the North Pole to the south
What does a magnetic compass contain?
A small bar magnet that points in the direction of the Earth’s magnetic field
What is produced when current flows through a conducting wire?
A magnetic field is produced around the wire
What determines the strength of the magnetic field around a current-varying wire?
The magnitude of the current flowing through the wire
What does a high concentration of field lines mean?
The field is strong
How is a plotting compass used to map out a magnetic field?
Place the compass of a piece of paper, draw an arrow in the direction the compass points. Repeat at different points on the paper. Join the arrows and make a complete field pattern
What is a solenoid?
A could of wire which creates a strong magnetic field when current passes through it.
Describe the magnetic field inside a solenoid
Strong and uniform
Is the field on the outside of a solenoid strong or weak? Why?
Weak because the fields from each coil cancel out, making the outside field weak
What is an electromagnet?
A solenoid with an added iron core.
What is the motor effect?
When a force is exerted between a magnetic field and a current-carrying conductor placed in that field
What rule is used to determine the force produced by the motor effect?
Fleming’s left-hand rule
What do each of the fingers represent in fleming’s left hand rule?
The forefinger = magnetic field
Second finger = current flow
Thumb = direction of force produced by motor effect
What factors affect the size of the force on a current-carrying wire in a magnetic field?
The magnitude of the current flowing through the conductor
The strength of the magnetic field that the conductor is placed in
If the direction of current in a current-carrying wire placed in a uniform magnetic field is reversed, what happens to the force?
The direction of the force is reversed
If the strength of the current in a current-carrying wire placed in a a uniform magnetic field is increased, what happens to the force?
The strength of the force is increased
