2018 Year 9 Electricity

Question 1

What is the charge of a proton, neutron and electron?

Answer 1

Protons have a positive charge, Electrons have a negative charge and neutrons have no charge

Question 2

If a charged particle has more electrons than protons, what will the charge be?

Answer 2

Negative

Question 3

If a charged particle has more protons than electrons, what will the charge be?

Answer 3

Positive

Question 4

What is the unit for current?

Answer 4

Amperes

Question 5

What is the unit for voltage?

Answer 5

Volts

Question 6

What is the unit for resistance?

Answer 6

Ohms

Question 7

What is the name of the instrument used to measure voltage?

Answer 7

Voltmeter

Question 8

What is the name of the instrument used to measure current?

Answer 8

Ammeter

Question 9

What happens to the brightness of two light globes when placed in a series circuit?

Answer 9

The globes are duller than a globe in a basic circuit

Question 10

What happens to the brightness of two light bulbs when they are placed in a parallel circuit?

Answer 10

The light bulbs are brighter in parallel than in series and would be the same as 1 lightbulb in a basic circuit

Question 11

What is a transformer?

Answer 11

A transformer increases or reduces voltage

Question 12

What is a generator?

Answer 12

A machine that uses electromagnetism to produce energy. It requires a coil and a magnet

Question 13

What does the resistance of a wire depend on?

Answer 13

The material the wire is made of, the length of the wire and the thickness of the wire

Question 14

What is an insulator? Give an example

Answer 14

An insulator is a material with such high resistance, electricity and heat is blocked from passing through completely. E.g. wood, air, water, brick,

Question 15

What is the colour of the active wire in an electrical cable?

Answer 15

Brown

Question 16

What is the colour of the neutral wire of an electrical cable?

Answer 16

Blue

Question 17

What is a fuse?

Answer 17

A fuse is a wire that will melts if too much current tries to pass through it

Question 18

What is a circuit breaker?

Answer 18

A switch that is activated by higher than normal current

Question 19

What is a residual current device?

Answer 19

A residual current device is used to detect current leaks. It stops any current from flowing if a leak is detected. It is also known as a safety switch

Question 20

What is a surge protector?

Answer 20

A device that turns off power to appliances if it detects massive and damaging increase in current

Question 21

What are the similarities and differences of static and current electricity?

Answer 21

Static electricity is the build up of charges. These charges stay in position until so much charge is built up that they jump across a gap as a spark or discharge to the air. Current electricity is the movement of charges, usually around the wires of a circuit

Question 22

State the voltage available from power point in Australia.

Answer 22

240 V

Question 23

Do power points supply AC or DC electricity?

Answer 23

AC

Question 24

When 3 batteries of 5V each are places in series, what is the total voltage?

Answer 24

15V

Question 25

What are the advantages of a parallel circuit over a series circuit?

Answer 25

Parallel circuits have one loop for each lightbulb. This means that unlike a series circuit, parallel circuits are independent of the others. If one light globe breaks in a series, they all stop working. If one breaks in a parallel, the rest keep working. Parallel circuits’ light bulbs shine brighter than series circuit because the electrons don’t need to go through multiple lightbulbs before going back to a power source

Question 26

What advantage does AC electricity have over DC electricity?

Answer 26

AC voltages can be changed into DC by using a rectifier. DC voltages can not.
AC can be increased or decreased using a transformer. DC voltages can not.
AC motors are relatively simple and more powerful than DC motors.
Transmission losses are lower in AC than DC.