IG Physics Section 6

When an external magnetic field is brought close to a piece of iron, the piece of iron will become magnetized. This is called :

• induced magnetism
• reduced magnetism
• introduced magnetism
• produced magnetism

Magnetic field lines around the outside of a bar magnet always run

• North to South
• South to North
• North to North
• in a perfect circle

To demagnetize a piece of iron

• hammer it
• heat it 
• apply A.C. to it
• all of these

Some materials that can't be magnetized:

• nickel, iron, gadolinium

• cobalt, copper, aluminium
• lead, copper, magnesium
• nickel, steel, chromium

Magnetic forces are caused by

• interactions between magnetic fields
• North poles
• South poles
• any permanent magnet

Ferrous materials contain

• iron

• steel

• fur

• copper

The right hand grip rule is used to find the direction of the magnetic field: in this case it will be 

• out of the screen on the left, into the screen on the right
• out of the screen on the right, into the screen on the left
• upwards
• downwards

The magnetic field strength varies according to field line density. In this picture the order of increasing strength is:

• A,C,D,B
• B,C,D,A
• A,D,B,C
• B,C,D,A

When a current is passed through a coil of wire in a clockwise direction

• the magnetic field direction will be into the coil opening
• the magnetic field direction will be out from the coil opening
• the magnetic field direction will be anti-clockwise
• none of these

To make the magnetic field around the wire stronger

• increase the current
• decrease the diameter of the wire
• increase the resistance of the wire
• make the wire longer