Light Flashcards
types of light waves
mechanical and electromagnetic
define mechanical waves
- move through a medium or a substance
- particles making up the wave only move a short distance, while the energy can travel a much larger distance
Define electromagnetic waves
- Propagate energy forward, but do not use a medium
- E.g. radio waves, microwaves, infrared radiation, visible light, ultraviolet light, x-rays and gamma rays
Define frequency
The number of crests that pass a given point within one second (Hz)
Define wavelength
- Shorter wavelengths are dangerous
More energy = more moving forward
Define amplitude
Half the wave
What rays go in and what rays go out
incident go in, reflected go out
Law of reflection
angle of incidence equals angle of reflection
Define refraction
- The bending is called ‘REFRACTION’
- The angle of refraction is different to the angle of incidence
describe the properties of light waves
Light has the properties of waves. Like ocean waves, light waves have crests and troughs.
light is transmitted from eye to brain
When light hits the retina, cells turn the light into electrical signals. These electrical signals travel from the retina through the optic nerve to the brain. Then the brain turns the signals into the images you see.
define crest
the maximum value of upward displacement within a cycle
define trough
the lowest point the medium sinks to
if the colour is showing red what is being absorbed
every colour but red
if the colour is showing black what is being absorbed
every color
