P4 - Electricity & Magnetism

Question 1

4 properties of magnets

Answer 1

-has magnetic field around it
-has 2 opposite poles
-attracts magnetic materials
-exerts little to no force to non-magnetics

Question 2

induced magnetism

Answer 2

process where unmagnetised objects temporarily gain magnetic capabilities when put inside the magnetic field of another magnet

Question 3

magnetic field

Answer 3

region in which a magnetic pole experiences a force

Question 4

2 ways to make magnetic magnets (stronger)

Answer 4

making magnet:
-put steel near a magnet (permanent weak magnetism)
stronger:
-stroking with opposite poles
-place in a long coil of wire and pass one-way current through the coil (iron coil = temporary, steel coil = permanent)

Question 5

the direction of a magnetic field at a point is?

Answer 5

the direction of the force on the N pole of a magnet at that point

Question 6

the direction of an electric field at a point is?

Answer 6

the direction of the force on a positive charge at that point

Question 7

electric field

Answer 7

region in which an electric charge experiences a force

Question 8

magnetic material

Answer 8

material that can be magnetised and attracted to magnets (ex. Iron, nickel, cobalt)

Question 9

ferromagnetics

Answer 9

strongly magnetic metals - magnetism of electromagnets can be turned on and off

Question 10

hard magnetic metals

Answer 10

hard to magnetize but don’t readily lose their magnetism (permanent magnets)

Question 11

soft magnetic metals

Answer 11

easy to magnetize but magnetism is temporary (magnetic effect can be switched on/off). it can also be reversed easily

Question 12

non-magnetic materials examples [5]

Answer 12

brass, copper, zinc, tin, aluminium, non-metals

Question 13

unmagnetized magnets

Answer 13

atomic magnets point in random directions

Question 14

magnetized magnets

Answer 14

atomic magnets line up and down with each other to create 1 big magnet

Question 15

demagnetized

Answer 15

atomic magnets are thrown out of line

Question 16

2 ways to demagnetize magnets

Answer 16

-hammered (atomic magnets gets thrown out of line)
-raised to a high temperature
-passing an alternating current (flows in several directions, back and forth) through it

Question 17

3 features of field lines

Answer 17

-never intersect
-always go N –> S
-closer the field lines, stronger the field

Question 18

how do you attract magnetic materials?

Answer 18

by inducing magnetism in them (make substance acquire magnetic property by aligning molecular magnets inside them)

Question 19

direct current

Answer 19

always flows in one fixed direction

Question 20

4 permanent magnet uses

Answer 20

-needles of compasses
-fridge door seals
-loudspeakers
-microphones