Electricity And Magnetism

Question 1

What is a material that easily allows an electric current?

Answer 1

An electrical conductor.

Question 2

What is a material that does not allow electric current?

Answer 2

An electrical insulator.

Question 3

Name some good electrical conductors.

Answer 3

Any metal, graphite (a form of carbon), salt water.

Question 4

Name some materials that are electrical insulators.

Answer 4

Wood, plastic, and most non-metals.

Question 5

What is the circuit symbol for a cell?

Answer 5

Draw the circuit symbol for a cell.

Question 6

What is the circuit symbol for a battery?

Answer 6

Draw the circuit symbol for a battery.

Question 7

What is the circuit symbol for a bulk?

Answer 7

Draw the circuit symbol for a bulk.

Question 8

What is the circuit symbol for a solenoid?

Answer 8

Draw the circuit symbol for a solenoid.

Question 9

What is the circuit symbol for a variable resistor?

Answer 9

Draw the circuit symbol for a variable resistor.

Question 10

What instrument is used to measure current?

Answer 10

An ammeter.

Question 11

What does an ammeter measure?

Answer 11

Current.

Question 12

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

Answer 12

Amperes, A.

Question 13

What happens if I increase the number of cells in my battery?

Answer 13

The current will increase.

Question 14

What happens when the charge moves through the cell?

Answer 14

It gains energy.

Question 15

What is the unit of potential?

Answer 15

Volt, V.

Question 16

What happens if I connect more bulbs in series?

Answer 16

The resistance will increase and the current will decrease.

Question 17

What is the unit of resistance?

Answer 17

Ohm, Ω.

Question 18

What is current?

Answer 18

The amount of charge passing a point each second.

Question 19

What is the important rule to remember at a junction in a circuit?

Answer 19

Total current in = total current out.

Question 20

What poles of a magnet attract each other?

Answer 20

The opposite poles (North and South).

Question 21

What happens when like poles of magnets come together?

Answer 21

They repel.

Question 22

Give some examples of magnetic materials.

Answer 22

Iron, steel, cobalt, nickel.

Question 23

Give some examples of non-magnetic materials.

Answer 23

Plastic, wood, paper, rubber, glass.

Question 24

Why does the Earth have a magnetic field?

Answer 24

The core of the Earth is a rotating ball of iron.

Question 25

What is a magnetic field?

Answer 25

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

Question 26

How are magnetic fields represented in diagrams?

Answer 26

Using magnetic field lines.

Question 27

How could you visualize the field around a magnet?

Answer 27

Using iron filings or a compass.

Question 28

What is the shape of a magnetic field around a wire?

Answer 28

Circular.

Question 29

How can we tell the direction of the magnetic field lines around a wire?

Answer 29

Using the right-hand 'thumbs up' rule: Thumb points in the direction of the current, fingers show the direction of the field lines.

Question 30

What is the effect of current flowing in a wire?

Answer 30

It creates a magnetic field.

Question 31

Draw the magnetic field around a solenoid.

Answer 31

Draw the magnetic field around a solenoid.

Question 32

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

Answer 32

1. Increase the current 2. Increase the number of turns on the coil 3. Add an iron core

Question 33

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

Answer 33

Electromagnets can be switched on and off.

Question 34

What is a relay circuit used for?

Answer 34

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

Question 35

List some uses of electromagnets.

Answer 35

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