WAVES Flashcards
What is an example of a transverse wave?
A ripple on water.
What is an example of a longitudinal wave?
Sound waves.
What do all waves do?
Transfer energy from one place to another.
What type of energy to ripples transfer?
Kinetic energy.
What type of energy do sound waves transfer?
Sound energy.
What is a transverse wave?
- has oscallisitions that move up and down.
- the oscillations are perpendicular to the direction of energy transfer.
What is the direction of energy transfer? (on both waves)
—–>
What is a longitudinal wave?
- sound waves travel as particles in the air move from side to side.
- the oscillations are parallel to the direction of energy transfer.
- need a medium to travel in.
What is the amplitude?
The maximum displacement of a point away from its undisturbed position. (the bit from the line to the peak of the wave).
What is the wavelength?
The distance from one point on one wave to the equivalent point on the adjacent wave. (from peak to peak) OR COMPRESSION/ RAREFRACTION TO THE OTHER,
What is the frequency?
The number of waves passing a point each second.
What is frequency measured in?
Hz.
What happens if we pass light through a prism?
A spectrum.
What is the electromagnetic spectrum?
Radio Waves-microwaves-infrared-visible light- ultraviolet- x rays- gamma rays.
How do you remember the electromagnetic spectrum?
RAW MEAT IS VERY UNSANITARY EXCEPT GIRAFFE.
Where can electromagnetic waves travel through?
A vacuum in space.
At what speed do electromagnetic waves travel in space?
3 X 10 (8)
What is the period?
The time in seconds for one wave to pass a point.
How do you work out the period?
1/frequency.
How do you workout wave speed?
Frequency X wavelength
What does wave speed mean?
The speed at which a wave moves through the medium (the speed at which energy is transferred).
Describe the required practical in detail.
- seperate two people 500m
- one holding a symbol
- person A clashes symbols
- B starts timing when they see
- They stop timing when they hear.
- To find out do distance/time.
What are the problems with the required practical?
-different reaction times.
How do we fix the problems with the required practical?
-have a large number of observers and calculate the mean.
What are microwaves absorbed by?
Foods that contain a water molecule.
What are light waves absorbed by?
Black surfaces.
What are microwaves reflected by?
metals.
What are light waves reflected by?
Shiny metallic surfaces.
When an electromagnetic wave is generated or absorbed where do the changes take place?
In the nuclei of atoms.
What are the dangers of UV rays?
cancer and premature aging.
What are the dangers of x-rays and gamma- rays?
Ionising radiation which can change the DNA.
What happens when we heat atoms?
electrons move to a higher energy level. When it returns it generates an electromagnetic wave/.
How are electromagnetic waves grouped?
In order of decreasing wavelength and increasing energy and frequency.
How are radio waves produced?
- When an alternating current is passed through a wire in a radio.
- the oscillating (vibrating) particles produce a radio wave.
What is the incident wave?
Wave fronts where all the waves are in phase with each other.
What happens when a wave refracts?
- when the wave hits a denser material it slows down.
- one side of the wave hits it first so slows down first.
- this causes the wave front to bend towards the normal line.
- wave fronts will be closer together as velocity decreases
- Frequency is unchanged.
