magnetism

Question 1

magnetic materials

Answer 1

materials that can be attracted to a magnet

steel (difficult to magnetism and demagnetise), iron (easily magnetised and demagnetised), cobalt, nickel

Question 2

non magnetic material

Answer 2

cannot be attracted to a magnet

copper, wood, plastic, brass

Question 3

magnetic induction

Answer 3

is the process whereby an object made of a magnetic material becomes a magnet when it is near or in contact with a magnet

Question 4

how to magnetise

Answer 4

stroking - stroke several times with a permanent magnet in one direction
direct current - placed in a solenoid, after a large current flows through the coils of wire for a period of time, the material will become magnetised

Question 5

how to demagnetise

Answer 5

heating and hammering
using a alternating current - the magnet is slowly withdrawn with the ac current which is still flowing until it is some distance away

Question 6

magnetic field

Answer 6

is a region surrounding a magnet in which a magnetic material experiences a magnetic force

Question 7

magnetic field lines

Answer 7

point away from the north pole and point towards the south pole
do not intersect
closer tgt indicate a stronger magnetic field

Question 8

neutral point

Answer 8

both magnets cancel each other out at that point

Question 9

temporary magnet

Answer 9

soft magnetic materials (iron)
easily magnetised and demagnetised
lose magnetism easily
electromagnet used in cranes to separate magnetic materials from non magnetic materials in scrapyards

Question 10

permanent magnet

Answer 10

hard magnetic materials
difficult to magnetise and demagnetise
retain their magnetism for a long time
magnetic door catches, compasses