waves Flashcards
What do waves do?
Transfer energy without transferring matter.
Longitudinal waves
Waves in which the vibrations are parallel to the direction of energy transfer
Transverse waves
Waves in which the vibrations are perpendicular to the direction of energy transfer.
Electromagnetic waves can travel through what
Can travel through a vacuum, no medium is needed
Examples of electromagnetic waves
light, radio, micro
Example of longitudinal waves
Sound
Amplitude
Height of the wave crest.
The bigger the amplitude of the waves…
…. the more energy the waves carry.
Examples of Transverse waves
light, radio, micro
Wavelength
The distance from one wavelength to the next
Frequency
The number of wave crests passing a fixed point every second
Electromagnetic Spectrum
Smallest - Largest: Gamma X-ray Ultraviolet Visible Infrared Micro Radio
Reflection
Law of reflection the angle of incidence is equal to the angle of reflection
The speed of the wavelength depends on the material it travels along
Refraction
The wave changes speed when going into the glass
When a wave reaches a boundary and goes into a different medium it’s speed changes
If the speed of a wave becomes smaller then the distance between wavefronts becomes shorter
Therefore the wave changes directions bends it retracts
Desperation of light
Light entering a prism is refracted
Different colours, wavelengths will refract at different angles
Red colour bends less than blue or violet
Richard of your gave battle in vain
Totally internally reflected
When light from a medium with a bigger optical density it hits the boundary at an angle bigger than the crtial angle then it is totally internally reflected
Dopple effect
s the change in frequency due to a wavefront moving closer
A wavefront becomes closer so the wavelength decreases.
Since the wave speed is at a constants the frequency higher
The sound has a high pitch
Wavelength increases
Frequency decreases
The hotter an object is…
… The more infrared radiation it emits.
How does infrared radiation affect the body?
It can damage or kill skin cells by heating them up.
Optical fibres
The glass fibre used to send light signals along.
Uses infrared radiation.
4 uses of infrared radiation
Optical fibres
remote control handsets
infrared scanners
infrared handsets
The shorter the length of radio waves:
The more information they can carry.
The shorter their range.
The less they spread out.
What are microwaves used for?
Satellite phones
TV links
Satellite TV
produced by microwaves to cook food
What are radio waves
TV broadcasting
What do electromagnetic waves carry
Information
What effect/harm does UV radiation have?
It is harmful to human eyes and can cause blindness.
What produces gamma rays?
Radioactive substances when unstable nuclei release energy.
Can sound waves travel through a vacuum?
no
Loud and High Pitched
high and close together
Loud and Low Pitched
high and spaced out
Increasing the loudness of a sound…
.. Increases its amplitude.
Increasing the frequency of a sound…
…Increases its pitch.
Positives of ultrasound
Non-ionising
Produces images of organ tissues as well as bones
What is the use of UV radiation?
produced by tanning bed lights to tan skin
used to detect conterfeit money
used to clean water
Give three properties (features) common to all EM waves
They all…
travel at the speed of light
all transverse waves
all transfer energy and information without transferring matter
all travel through a vacuum
List the EM spectrum in order of decreasing frequency
Gamma - gardens
X-ray - expensive
UV - unusual
Visible - very
IR - in
Microwave - mate
Radio - rabbits
What is the relationship between wavelength and frequency of a wave?
As frenqucy increases the wavelength decreases
They are inversely proportional
What is the use of X-rays?
Used to detect breaks in bones
used to detect crystal structure in salts
