Electrical Systems and Control

Question 1

What is the difference between permanent magnets and temporary magnets?

Answer 1

Permanent magnets keep their magnetism for an indefinite period of time.
Temporary magnets lose their magnetism quickly.

Question 2

What is magnetism?

Answer 2

Magnetism is a force that can attract (pull closer) or repel (push away) objects that have a magnetic material like iron inside them.

Question 3

What is a magnetic field?

Answer 3

The space in which a magnetic objects magnetic effect is felt. The Earth has a magnetic field.

Question 4

Why is it important to us that the Earth has a magnetic field?

Answer 4

The Earth’s magnetic field protects us from harmful radiation from space.

Question 5

What is a Lodestone?

Answer 5

A Lodestone is a naturally occurring magnetic rock made of magnetite.

Question 6

True or False

Like poles attract each other; unlike poles repel each other.

Answer 6

False:

The North Pole of a magnet attracts the South pole of another magnet and repels the North Pole of another magnet.

Question 7

When were the first magnetic compasses used?

Answer 7

Chinese 1000 years ago

Question 8

What is a compass?

Answer 8

A device having a magnetic needle that indicates direction on the earth’s surface by pointing toward the north.

Question 9

Name three ways to handle magnets correctly.

Answer 9

1) Store Magnets in their boxes in safe place. They should not be stored near electronic equipment which magnets can damage.
2) Store magnets with their keepers in place which keeps them strong.
3) Never drop, hit or heat a magnet.

Question 10

What are the poles of the magnet?

Answer 10

The ends of the magnet where the magnetic force are strongest.

Question 11

What are keepers?

Answer 11

Keepers are iron bars that are placed between the poles of a permanent magnet to preserve the magnetic strength.

Question 12

True or False.

All metals and non-metals are attracted to magnets.

Answer 12

False. No non-metals are attracted to magnets and only some metals are attracted to magnets. Most metals are alloys i.e. a mixture of one or more metals.

Question 13

Define recycling

Answer 13

Recycling is the conversion of used materials into new products.

Question 14

What are ferrous metals?

Answer 14

Ferrous metals contain iron.

Non-ferrous metals do not contain iron.

Question 15

Are non-ferrous metals magnetic?

Answer 15

No. They are not magnetic because they do not contain iron.

Question 16

Name 3 useful features of non-ferrous metals.

Answer 16

They are malleable, they are resistant to corrosion and they conduct electricity.

Question 17

Define corrosion and malleable

Answer 17

Corrosion: To rust or disintegrate when exposed to certain conditions such as salt and water.
Malleable: can be hammered or pressed into another shape.

Question 18

Name four materials that can be recycled

Answer 18

Paper, Glass, Plastic, Metals

Question 19

Why is recycling important?

Answer 19

By reusing the material we throw away, we reduce the amount of waste thrown away and used to fill out huge garbage dumps.

Question 20

How can recycling help your school?

Answer 20

Raise Funds;
Teach children and teachers about the environment; and ways we can help reduce the impact of our lifestyles on the planet.

Question 21

What is an electric circuit?

Answer 21

An electric circuit allows the flow of electrical energy through a circuit.

Question 22

What does an electric circuit need to function?

Answer 22

An electrical energy source, electrical components and wires that are connected to one another.
An electrical energy source such as a battery or cell. It pushes electricity through the circuit.
Connecting wires are made of a material that can conduct electricity (non-ferrous metal) and usually link the electrical energy source and the electrical components.
Electrical components include: lights and switches.

Question 23

Why is insulation important for connecting wires in an electrical circuit?

Answer 23

Insulation ensures that the electrical energy follows the designed path. If the connecting wires are uninsulated, the electrical energy could take a different route or a shorter route than intended. This is called a short circuit.

Question 24

Why is a short circuit not a good thing in an electrical circuit?

Answer 24

It can make the circuit not work as intended/waste electrical energy.

Question 25

What is electrical energy?

Answer 25

The energy that flows through an electrical circuit.