Electricity and Magnetism

Question 1

What is electricity and its use

Answer 1

Electricity is the movement of electric charge. It is useful for energy transfers involving electrical energy.

Question 2

Describe the difference between static electricity and current electricity

Answer 2

Static electricity is caused by the accumulation (charge at rest) of charge on the surface of the body.

Current electricity is caused by the movement of charge or electrons

Question 3

Explain what a conductor is

Answer 3

Conducts electricity sinceit offers little or no resistance to the flow of electrons

Question 4

Explain what an insulator is

Answer 4

An insulator does not conduct electricity. An insulators a material thatresists the flow of electrons

Question 5

Explain static electricity as a buildup of charge

Answer 5

Static buildup is when electric charges are exchanged between two surfaces that are in contact.
In this process, one object takes on a positive charge and the other a negative charge. It is because of this that static electricity builds up on the surface of objects.

Question 6

Describe some uses of static electricity

Answer 6

Photocopiers and inkjet printers use static electricity to ensure that toner sticks to the paper. Electrostatic paint spraying uses static electricity to get an even paint

Question 7

Explain why static electricity can be dangerous

Answer 7

Aeroplanes and rescue helicopters.

Question 8

State the conditions required for electrons to move along a conductor

Answer 8

For electrons to flow continuously through a conductor, there must bea complete, unbroken path
for them to move both into and out of that conductor.

Question 9

Use standard circuit symbols to describe a simple electric circuit

Question 10

Explain the difference between a series circuit and a parallel circuit

Answer 10

Series:
- components are all connected one after another
- there is only one path electrons can take
- Voltage of the battery is shared across all of the components and current is the same

Parallel:
- components are connected side to side
- several paths are available to the electrons.
- Voltage of the battery is the same and current is shared across all of the components

Question 11

Explain electric current

Answer 11

An electric current is a flow of charge.

Question 12

what is currents measured in

Answer 12

Amps from an ammeter (A).

Question 13

What is the law of conservation of charge

Answer 13

Law of conservation of charge says thatthe net charge of an isolated system will always remain constant.

Question 14

What is energy carried by

Answer 14

Electrons

Question 15

What does voltage measure

Answer 15

Voltage measures the energy carried by electrons.

Question 16

What does voltmeters measure

Answer 16

Voltage and compares energy on each side of the component and shows the energy difference between 2 points.

Question 17

Understand the definition of power

Answer 17

Time and rate of doing work or delivering energy.

Question 18

Calculate power using voltage and other data

Answer 18

Power in Watts is calculated bymultiplying voltage in Volts times current in Amps.
- P = VA

Question 19

Explain what a “kilowatt-hour” is

Answer 19

kWh stands for kilowatt hour (kWh) – it’s the way we measure energy in the home.

total cost: total kWh x price of 1 kWh

Question 20

Calculate the cost of electricity using power and time data

Answer 20

Multiply the power rating (watts) by the amount of time (hrs) and divide by 1000.

Question 21

Describe methods of controlling electric currents

Answer 21

Switch: A device that interrupts the electron flow in a circuit.

Fuse: If too much current flows, the fuse wire rises to a higher temperature and melts, which opens the circuit but destroys the fuse.

Circuit breakers: A type of electrical switch which heats up and cuts the power when current levels are too high.

Question 22

List the safety precautions for an electrical accident

Answer 22

• Always Cut the Power
• Investigate Flickering Lights
• Don’t Use Extension Cords Long-Term

Question 23

Understand magnetic attraction and repulsion

Answer 23

Like sides (south and south, north and north) will repulse.

Unlike sides (south and north) will attract.

Question 24

Map magnetic fields

Question 25

State which types of materials are magnetic

Answer 25

Ferromagnetic substances; nickel, iron, and cobalt. Steel is an alloy containing iron, therefore it is also ferromagnetic.

Question 26

Understand what happens inside a magnet

Answer 26

Magnetic materials have regions that are magnetic domains. These are not lined up in a direction and so tend to cancel each other out. However, when a magnet is made these domains line up making it magnetic.

Question 27

Test magnet strength

Answer 27

Investigate the weight of what the magnet can lift up.

Question 28

State how to make a magnet

Answer 28

1. Cool iron in a magnetic field
2. Move a magnet up and down on a piece of iron
3. Hammer a nail in a magnetic
4. Put a piece of iron in an electric field

Question 29

Understand that electricity and magnetism are linked

Answer 29

A changing electric field creates a magnetic field, and a changing magnetic field creates an electric field.

Question 30

Make and test a simple electromagnet

Question 31

Investigate and state the factors that affect the strength of a simple coil electromagnet

Answer 31

1. Current: increasing the current in the wire
2. Coils: the more coils the stronger the magnet
3. Core: adding a core of iron such as a single steel bar or bundle of wires.

Question 32

State some applications of electromagnets

Question 33

What is an electromagnet/solenoid

Answer 33

A wire carrying a current that has a magnetic field around it.

Question 34

What is a motor

Answer 34

Converts electrical energy into kinetic energy.

Question 35

What is a generator

Answer 35

Something that generates electricity

Question 36

Why is an electromagnet better

Answer 36

An electromagnet can always be turned on and off.