P14 - Light Flashcards
define:
normal
of a mirror
the line perpendicular to the plane
define:
angle of incidence
θi
the angle between the normal and the incident ray
define:
angle of reflection
θr
the angle between the normal and the reflected ray
define:
law of reflection
θi = θr
define:
refraction
bending of light rays when they enter different mediums
Why does refraction occur?
refraction occurs because light travels at different speeds in different mediums
what instrument is used to create light rays
RP
ray box
list:
3 terms that are used to describe an image
- real / virtual
- upright / inverted
- magnified / diminished
define:
real image
an image that can be projected onto a screen
define:
virtual image
an image that seems to come from behind the lens or mirror
define:
specular reflection
caused by a smooth surface that reflects light rays in one direction
define:
diffuse reflection
caused by a rough surface that scatters light rays in different directions
define:
refraction rule
if light rays slow down, they bend towards the normal
and vice versa
2 types of lenses
- convex
- concave
what do convex lenses do
causes rays to converge to the principal focus
what do concave lenses do
causes rays to diverge
define:
principal focus
the point where light converges or seems to converge
define:
focal length
distance from the centre of the lens to the principal focus
formula:
magnification
magnification = image height / object height
symbol:
convex lens
Arrows facing out
|
∨
symbol:
concave lens
Arrows facing in
V
|
What method is used to find images through a lens?
ray diagram
Formation of an image by a convex lens
when the object is further than the principal focus
real, inverted, diminished
Formation of an image by a convex lens
when the object is between the principal focus and the lens
virtual, upright, magnified
Formation of an image by a concave lens
virtual, upright, magnified
