Light Flashcards
Speed of light
300,000km/hr
What travels just as fast as light?
Electromagnetic radiation
What is light made up of?
Photons which are particles that travel as a wave
What kind of energy is light?
radiant energy
Purpose of the electromagnetic spectrum
To show us the different types of light
What kind of wave is light?
Transverse wave
What is light?
Energy that travels as an electromagnetic wave
When light hits a wave, what are the 3 things that can happen?
It can be transmitted, reflected or absorbed
What happens when light is transmitted
When light passes through the object
What happens when light is reflected
light bounces off the object
What happens when light is absorbed
When light is taken into the object
Transparent objects
Materials like glass that allow light to pass through them
Transculent objects
- Objects that allow only some light to be pass-through
- can’t see through objects clearly like a foggy mirror or clouds
Opaque objects
Objects that absorb or reflect all light eg. concrete floor
or that light can’t pass through at all
What depends on how reflective an object is
how reflective an object depends on how smooth the surface is
Law of reflection
Angle of incidence=Angle of reflection
Incident ray
Ray of light that hits a surface
Angle of reflection
Angle between the reflected ray and the normal
Whats the normal
The imaginary line drawn perpendicular to the mirror
Angle of incidence:
Angle between the incident ray and the normal
Reflected ray
A ray of light that leaves the mirror
Plane mirrors
Plane mirrors are flat mirrors that produce a virtual image
refraction
is the bending of light rays that occur when light at angle travels from one medium to another of different density
when does light bend
Light bends when it changes speed
Virtual images
Images that are reversed
Refracted Ray
The bent ray
What happens when light enters a denser medium
The light ray slows down and bends towards the normal
What happens when a light ray enters a less dense medium
The light ray speeds up and bends away from the normal.
The lower the refractive index….
The less dense the medium is and the faster light travels through it.
When does the light not bend?
Light doesn’t bend when it enters a new medium of 90 degrees.
Convex lenses
Convex lenses at the centre than the edges and cause light rays to converge.
The focus point
Where the rays meet or cross
Concave lenses
Concave lenses are thinner at the centre than at the edges and cause light rays to diverge
What is the result of refraction
the bending of light rays
Lens
A curved piece of transparent material such as glass or plastic
Focal length of convex lens
Focal length is the distance from the focus to the middle of the lens for the convex lens
Focal length of concave lense
Focal length is from the left side of the focus to the middle of the lense
What lens has a virtual focus point
Concave lens
What does the amount of refraction depend on
The amount of refraction that takes place depends upon the angle that the light ray hits the surface of an object. Lenses make use of this to bring rays to a point.
What is a magnifying lens
Concave lens
What should a ray diagram start with
A light source
how refraction of light through transparent materials occurs,
Transparent materials have a less dense medium causing light rays to speed up. When light rays speed up they refract.
how refractive index determines if the light is refracted towards or away from the normal.
Whether the light rays bend towards or away from the normal is determined by the refractive index. When light rays enter a denser medium, they bend towards the normal and when they enter a less dense medium they bend away from the normal.
Light sensitive back of the eye
Retina
Rocks at the bottom of a stream always look like they are in shallower water than they actually are. This is caused by?
refraction
