Year 9 Science Flashcards
What is the waves equation?
Velocity = frequency x wavelength v= f x l
What is the speed of light?
3 x 10 to the 8 meters per second
Or 300,000 km/s
What is wavelength measured in?
Metres symbol l for lambda
Define frequency
Frequency (f) is the number of waves passing a point per second. ( waves per second Hertz)
Define velocity
Velocity (v) =. Ms to -1
In the electromagnetic spectrum what properties does a short wave length iniducate?
The shorter the wavelength the higher the frequency and the higher the energy of the wave
Name two types of waves and define them
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
What is amplitude?
The height of the wave
What is a trough?
The low point if the wave
What is crest
The high point of the wave
How do you measure wavelength?
The distance between the crests of two waves is the wavelength
What is reflection
Reflection= the angle of incidence is the same as the angle of reflection
What is refraction
The angle of incidence is different from the angle of refraction (eg light rats through a water bottle)
What is dispersion
Dispersion= the separation of visible light into its components eg a rainbow Roygbiv red orange yellow green indigo violet
What is viewing colour
The colour reflected by a surface when all other colours are absorbed
What is Ohms law?
V = I x R Volts = currents amps times resistance
What do voltmeters measure?
Volts
What do ammeters measure?
Amps or amperes ( current )
What do multimeters measure?
Resistance. ( ohms)
Draw a series circuit name some properties
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
Draw a parallel circuit name some properties
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
Draw common circuit symbols
Wire, switch open, closed, resistor, single cell, battery, light bulb
What is a transformer?
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
What type of power goes into Australian homes?
Alternating current 240-240V
Describe the colours and uses of power wires n Australian homes?
Brown= active Blue= neutral Green/yellow= earth
What does a safety switch do?
It is designed to turn the power off if a power overload or leakage occurs. Helps to prevent electrocution
What does the resistance of a wire depend upon?
- The type of material the wire is made of
- The length of the wire
- The thickness of the wire
What type of wire is use in circuits and why?
Copper due to its low electrical resistance
What is a conductor?
A conductor allows a current to flow within them eg metal, Locke copper aluminium, nichrome
What do insulators do?
Insulators do not allow electricity to flow within them, eg. Wood plastic rubber
What is myopia?
An eye condition also called short sighted ness or near sighted
What s hyperopia?
An eye condition also also know as far sightedness or farsighted
What is the iris?
Coloured part of the eye
What is the pupil?
Black part of the eye where the lens is
What is the cornea?
Back part of the eye where the Image is focused
What is the optic nerve?
Transmits signals between the eye and the brain
Describe an electromagnet?
An electromagnet is bat described as a coil of copper wire into which an iron core has been inserted
Describe electromagnetic radiation
Electromagnetic radiation is best described as an electric wave and a magnetic wave moving together at right angles to each other
What type of light is responsible for sunburn and skin cancer?
Ultraviolet light. Known as UV
What do we use infrared light for?
Heating purposes and night vision
Name three types of variables
- Independent variables= the variable that the scientist chooses to change
- Dependent variable= the variable that the scientist chooses to measure
- Controlled variable= the list of variables that the scientist chooses to keep the same
Why are X-ray’s useful?
X-rays are able to be used for medical purposes due to their ability to penetrate skin and tissue but not bone
What does the electromagnetic spectrum consist of?
- Radio
- Microwaves
- Infrared
- Visible
5. - X rays
- Gamma rays
Rmi vxg
