magnetism and electromagnetism

Question 1

what are the ends of magnets called

Answer 1

poles

Question 2

define a magnetic field

Answer 2

area around a magnet where other magnetic materials would experience a force

Question 3

list 3 magnetic elements that can be magnetised

Answer 3

iron
nickel
cobalt

Question 4

how can an unmagnetised material become magnetised?

Answer 4

place in a magnetic field

Question 5

what is a solenoid?

Answer 5

a coil of insulated wire

Question 6

what is an electromagnet

Answer 6

a solenoid that has an iron core

Question 7

what is the motor effect?

Answer 7

when a current flows through a wire that is at an angle to a magnetic field it will experience a force

Question 8

how can a force be increased (3)

Answer 8

• increase current
• use a stronger magnet
• having a longer length of wire in the magnetic field

Question 9

how can the force on a wire be reversed (2)

Answer 9

• reverse current
• swap north and South of magnet

Question 10

how could you make a motor spin faster? (3)

Answer 10

• stronger magnet
• higher current
• adding turns to coil

Question 11

how could you make a motor spin the other way? (2)

Answer 11

swap north and south poles
current flows in opposite direction

Question 12

what is the generator effect?

Answer 12

where you induce a potential difference using a magnetic field.

Question 13

how can the size of induced p.d. get increased? (3)

Answer 13

• moving magnetic coil faster
• use a stronger magnet
• have more turns in coil of wire

Question 14

how can the direction of induced potential difference be changed? (2)

Answer 14

• move magnet/coil in opposite direction
• swap month and south of the magnet bering used

Question 15

how would the induced p.d. of an alternate current generator increase? (3)

Answer 15

• coill rotated faster
• magnet made stronger
• more turns in coil

Question 16

transformers function

Answer 16

increase or decrease the size of the p.d. which also causes the current to increase or decrease

Question 17

step-up transformer function

Answer 17

increases the alternating p.d. and decreases current.

Question 18

step-down transformer function

Answer 18

decreases alternating p.d. and increases the current