Light Waves Flashcards
Angle of incidence = ?
Angle of reflection
when light hits a mirror, it must pass through the?
focal point/focus
concave mirror towards or away from focal point?
towards focal point
define refraction
refraction is the change in speed of a wave in a different medium
when a wave bends, is that refraction?
no, it is a sign of refraction, which means speed of wave and subsequently, wavelength have changed
when a wave enters a denser medium, what occurs?
wavelength decreases, and from v = f*lambda, velocity decreases
when a wave enters a less dense medium, what occurs?
wavelength increases, velocity increases
when a wave enters a medium, what remains constant?
frequency remains constant
when a wave (non parallel to the surface) enters a denser medium, does it bend towards or away from the normal?
towards the normal for denser mediums
when a wave (non parallel to the surface) enters a less dense medium, does it bend towards or away from the normal?
away from the normal for less dense mediums
Snell’s law is?
sinx1 / sinx2 = v1 / v2 = n2 / n1
snell’s law for angles and refractive index only
sinx1n1 = sinx2n2
why can’t a refractive index be <1
because nothing can travel faster than the speed of light
what is the critical angle
the critical angle is the angle of which a wave refracts along the surface that it touches, (parallel)
what happens if the angle of incidence is greater than the critical angle?
total internal reflection occurs. (total internal reflection can only occur from Dense to less dense)
provide an example of the use of TIR
optical fibres (NBN) use total internal reflection to carry digital data in the form of light
what is cladding
use of less dense mediums to prevent light from escaping via reflection
describe constructive interference
when waves are in the same phase (pattern) and essentially increase the strength by becoming a single wave
describe destructive interference
when waves out of phase cancel each other out
describe superposition
when one wave is placed on top of another, and the wave changes
what is the virtual image
image that appears on the opposite side of the mirror
