P13 Flashcards
In a magnet do opposite poles attract ?
Yes
In a magnet do like pole attract ?
No
What is the region around the magnet called ?
A magnetic field
What happens when any other magnetic materials are placed in a magnetic field ?
They experience a force caused by the first magnet
What metals are magnetic ?
Iron , nickel , cobalt and steel
If you keep a magnetic metal next to a magnet what happens ?
The metal is attracted to the magnetic
How do you plot a magnetic field ?
Step 1 - using a pencil , put a dot on the paper where the needle is pointing .
Step 2- place the plotting compass so that the needle points to the dot you have made
Step 3 - draw a new dot at the other end of the needle .
Step 4 - keep going until you either go off the page or you loop back around to the other side of the magnet .
Step 5 - keep repeating this process completing as many lines as possible within the lesson .
What is induced magnetism
Magnetism created in an unmagnetised magnetic material when the material is placed in the magnetic field
What is a solenoid ?
A wire coiled into a spiral
How do you find the direction of a field around a straight wire ?
Use the right hand grip rule
What is a uniform field ?
Wherever you measure the magnetic field in solenoid it is equal
In a solenoid is the magnetic field strong ?
Yes
In a solenoid how are the magnetic field lines represented ?
Ontop of each other in equal lengths
Is the magnetic field stronger in a solenoid or in a straight line ?
A solenoid.
To increase the strength of the solenoid what could we do ? Three ways ?
Increase the current
Add more turns to the coil
Add an iron core ( making an electromagnetic )
What is an electromagnet ?
An electromagnet is a solenoid in which the isolated wire is wrapped around an iron bar . When a current is passed along a wire , a magnetic field is created around the wire . Because of this, the magnetic fields of wire magnetised to the core.
What increases the strength of an electromagnetic ?
An iron core at the centre of a coil of wire
What is the motor effect ?
When a conductor carrying a current is placed in a magnetic field the magnet producing the field and the conductor exert a force on each other
What is fleming’s left-hand rule ?
Fleming’s left-hand rule represents the relative orientation of the force, the current in the conductor and the magnetic field .
In Fleming’s left-hand rule , what does the first finger represent ?
Field
In Fleming’s left hand rule what does the second finger represent ?
Current
In Fleming’s left hand rule , what does the thumb represent ?
Movement
The size of the force produced on a current carrying wire in a magnet can be calculated . What key variables need to be considered to calculate this force ?
. Size of current
. Magnetic field strength
. Length of wire in field
For a conductor at right angles to a magnetic field and carrying a current , what is the equation ?
Force = magnetic flux density x current x length
