Year 9 Science

Question 1

What is the waves equation?

Answer 1

Velocity = frequency x wavelength
v= f x l

Question 2

What is the speed of light?

Answer 2

3 x 10 to the 8 meters per second

Or 300,000 km/s

Question 3

What is wavelength measured in?

Answer 3

Metres symbol l for lambda

Question 4

Define frequency

Answer 4

Frequency (f) is the number of waves passing a point per second. ( waves per second Hertz)

Question 5

Define velocity

Answer 5

Velocity (v) =. Ms to -1

Question 6

In the electromagnetic spectrum what properties does a short wave length iniducate?

Answer 6

The shorter the wavelength the higher the frequency and the higher the energy of the wave

Question 7

Name two types of waves and define them

Answer 7

Transverse eaves: the wave particles oscillate at right angles to the waves direction ( eg wave at beach)
Longitudinal= wave particles oscillate in same direction of wave eg sound wave

Question 8

What is amplitude?

Answer 8

The height of the wave

Question 9

What is a trough?

Answer 9

The low point if the wave

Question 10

What is crest

Answer 10

The high point of the wave

Question 11

How do you measure wavelength?

Answer 11

The distance between the crests of two waves is the wavelength

Question 12

What is reflection

Answer 12

Reflection= the angle of incidence is the same as the angle of reflection

Question 13

What is refraction

Answer 13

The angle of incidence is different from the angle of refraction (eg light rats through a water bottle)

Question 14

What is dispersion

Answer 14

Dispersion= the separation of visible light into its components eg a rainbow Roygbiv red orange yellow green indigo violet

Question 15

What is viewing colour

Answer 15

The colour reflected by a surface when all other colours are absorbed

Question 16

What is Ohms law?

Answer 16

V = I x R
Volts = currents amps times resistance

Question 17

What do voltmeters measure?

Answer 17

Volts

Question 18

What do ammeters measure?

Answer 18

Amps or amperes ( current )

Question 19

What do multimeters measure?

Answer 19

Resistance. ( ohms)

Question 20

Draw a series circuit name some properties

Answer 20

Current us same around circuit
Voltage is shared between the resistors
If a light bulb is added they all get duller
Minimum wire is required
Single switch
If one appliance fails the whole circuit fails

Question 21

Draw a parallel circuit name some properties

Answer 21

The current is shared between the branches
The voltage us the sane for each resistor
If a light bulb is added they all stay the same brightness
More wire required
If one appliance fails the others will still work
A house circuit is one large parallel circuit

Question 22

Draw common circuit symbols

Answer 22

Wire, switch open, closed, resistor, single cell, battery, light bulb

Question 23

What is a transformer?

Answer 23

A device that increases or decreases the voltage before use by an appliance .
It can also change alternating current into direct current for use in household appliances. Direct current is used by devices that can also be powered by batteries

Question 24

What type of power goes into Australian homes?

Answer 24

Alternating current 240-240V

Question 25

Describe the colours and uses of power wires n Australian homes?

Answer 25

``` Brown= active Blue= neutral Green/yellow= earth ```

Question 26

What does a safety switch do?

Answer 26

It is designed to turn the power off if a power overload or leakage occurs. Helps to prevent electrocution

Question 27

What does the resistance of a wire depend upon?

Answer 27

1. The type of material the wire is made of 2. The length of the wire 3. The thickness of the wire

Question 28

What type of wire is use in circuits and why?

Answer 28

Copper due to its low electrical resistance

Question 29

What is a conductor?

Answer 29

A conductor allows a current to flow within them eg metal, Locke copper aluminium, nichrome

Question 30

What do insulators do?

Answer 30

Insulators do not allow electricity to flow within them, eg. Wood plastic rubber

Question 31

What is myopia?

Answer 31

An eye condition also called short sighted ness or near sighted

Question 32

What s hyperopia?

Answer 32

An eye condition also also know as far sightedness or farsighted

Question 33

What is the iris?

Answer 33

Coloured part of the eye

Question 34

What is the pupil?

Answer 34

Black part of the eye where the lens is

Question 35

What is the cornea?

Answer 35

Back part of the eye where the Image is focused

Question 36

What is the optic nerve?

Answer 36

Transmits signals between the eye and the brain

Question 37

Describe an electromagnet?

Answer 37

An electromagnet is bat described as a coil of copper wire into which an iron core has been inserted

Question 38

Describe electromagnetic radiation

Answer 38

Electromagnetic radiation is best described as an electric wave and a magnetic wave moving together at right angles to each other

Question 39

What type of light is responsible for sunburn and skin cancer?

Answer 39

Ultraviolet light. Known as UV

Question 40

What do we use infrared light for?

Answer 40

Heating purposes and night vision

Question 41

Name three types of variables

Answer 41

1. Independent variables= the variable that the scientist chooses to change 2. Dependent variable= the variable that the scientist chooses to measure 3. Controlled variable= the list of variables that the scientist chooses to keep the same

Question 42

Why are X-ray's useful?

Answer 42

X-rays are able to be used for medical purposes due to their ability to penetrate skin and tissue but not bone

Question 43

What does the electromagnetic spectrum consist of?

Answer 43

1. Radio 2. Microwaves 3. Infrared 4. Visible 5. 6. X rays 7. Gamma rays Rmi vxg