Light Flashcards
(31 cards)
When rays of light pass through a transparent medium to another
They change speed
If entering the medium at an angle other than 90 degrees to the surface, they change direction
Air- glass
Towards the normal
Glass- air
Away from the normal
If the incident ray is the same as the critical angle
The ray is refracted along the interface (angle of refraction = 90 degrees)
If the incidence ray is bigger than the critical angle
Total internal reflection occurs
Total internal reflection occurs when
Light is travelling from a more dense medium to a less dense. Medium
The angle of incidence is greater than the critical angle
Glass- air
transverse waves
the particles of the medium vibrate in a direction perpendicular to the direction in which the wave is being propagated
examples of transverse waves
all electromagnetic waves and water waves
longtiundial waves
the particles of the medium vibrate in a direction parallel to the direction of propagation of the wave
examples of longtiundial waves
sound waves, primary seismic waves
consist of compressions and rarefractions
compressions
a region where the particles of the medium move towards each other giving areas of increased pressure
rarefraction
a region where the particles of the medium have moved away fromm each other, giving an area of decreased pressure.
the electromagnetic spectrum is arranged in order of
long wavelength, low frequency low energy (radio waves)
radio waves
used for broadcasting and communication
microwaves
used for cookers and satellite transmittions
bad effect- internal heating of body tissue
infra-red
heaters and night vision
effect on body- skin burns
to limit the effect- avoid radiation, wear suitable clothes
visible light
optic fibers and photography
effect on body- eye damage
limit- avoid radiation, wear sunglasses
x rays
a photographic or digital image of the internal composition of something,
effect- damage and possible mutation of cells, could cause cancer
limit- avoid radiation, use protective shielding
ultraviolet
fluorescent lamps
effect- damage to surface cells and blindness
limit- avoid radiation, wear suitable clothes and sunglasses
gamma rays
sterilising food and medial equipment
effect- damage and possible mutation of cells, which could cause cancer
limit- avoid radiation. use protective shielding
waves transfer
energy and information without transferring matter
all of the electromagnetic sectrum
are transverse waves can transmit energy have the same speed can travel through vacuum can all be reflected
the height of the wave is
amplitude
the length of the wave is
wavelength
