electricity and magnetism

Question 1

A material which easily allows an electric current is

Answer 1

an electrical conductor

Question 2

A material which does not allow an electric current is

Answer 2

an electrical insulator

Question 3

Name some good electrical conductors

Answer 3

Any metal (some are better than others!), graphite (a form of carbon), salt water

Question 4

Name some good electrical insulators

Answer 4

Wood, plastic (most non-metals in fact)

Question 5

Draw the circuit symbol for a cell

Question 6

Draw the circuit symbol for a battery

Question 7

Draw the circuit symbol for a bulb

Question 8

Draw the circuit symbol for a switch

Question 9

Draw the circuit symbol for a variable resistor

Question 10

Draw the circuit symbol for an ammeter

Question 11

What instrument is used to measure current?

Answer 11

Ammeter

Question 12

What does an ammeter measure?

Answer 12

Current

Question 13

What is the unit of current and what is its symbol?

Answer 13

Amperes, A

Question 14

If I increase the number of cells in my battery the current will…?

Answer 14

Increase

Question 15

When the charge moves through the cell it gains…?

Answer 15

energy

Question 16

Energy per unit charge is also known as….

Answer 16

potential

Question 17

What is the unit of potential?

Answer 17

volt, V

Question 18

If I connect more bulbs in series with each other the resistance will…and the current will….

Answer 18

resistance will increase and the current will decrease

Question 19

What is the unit of resistance

Answer 19

ohm, Ω

Question 20

What is current?

Answer 20

The amount of charge passing a point each second

Question 21

At a junction in a circuit what is the important rule to remember?

Answer 21

total current in = total current out

Question 22

Which poles of a magnet attract each other?

Answer 22

The opposite poles (North and South)

Question 23

What happens when like poles of magnets come together

Answer 23

They repel

Question 24

Give some examples of magnetic materials

Answer 24

Iron, Steel, Cobalt, Nickel

Question 25

Give some examples of non-magnetic materials

Answer 25

Plastic, Wood, Paper, Rubber, Glass

Question 26

Why does the Earth have a magnetic field

Answer 26

The core of the earth is a rotating ball of Iron

Question 27

What is a magnetic field?

Answer 27

The region around a magnet where other magnetic materials experience a force

Question 28

How are magnetic fields represented in diagrams?

Answer 28

Magnetic field lines

Question 29

How could you visualise the field around a magnet?

Answer 29

Iron filings, or using a compass

Question 30

Draw the magnetic field around a bar magnet

Question 31

Draw the magnetic field around the Earth

Answer 31

Remember - the Earth’s geographic north pole is a magnetic south pole (we still call it magnetic north when referring to where our compass needle points!)

Question 32

What is the shape of a magnetic field around a wire and how can we tell the direction of the field lines?

Answer 32

Circular. Right hand “thumbs up” rule. Thumb points in the direction of the current, the fingers curl in the direction of the field

Question 33

When a current flows in a wire a magnetic field is generated. What do we call this effect?

Answer 33

Electromagnetism

Question 34

Draw the magnetic field around a coil/solenoid

Question 35

Name 3 ways to increase the strength of the magnetic field around a solenoid

Answer 35

• Increase the current
• Increase the number of turns on the coil
• Add an iron core

Question 36

What is one of the major advantages of an electromagnet compared to a permanent magnet

Answer 36

Electromagnets can be switched on and off

Question 37

What is a relay circuit used for?

Answer 37

To activate high voltage circuits using low voltage circuits (this protects the user from high currents)

Question 38

List some uses of electromagnets

Answer 38

In relays (e.g. to switch of floodlights or x-ray machines in hospitals), in scrapyards to move parts, maglev trains, in electric motors, in rollercoaster braking