Topic 10 Visible Light Flashcards
The properties of light are: (list three properties)
Light is emitted by luminous objects
Light travels in straight lines
Light travels much faster than sound
The change in direction of a wave passing from one medium to another caused by it’s change in speed.
Refraction
Spreading of something over an area.
Dispersion
Light travels to the material and is unable to travel any further.
Absorbed light
Light that has changed direction, but continues to travel in the original material.
Reflected light
Length of one wave pattern.
Wavelength
Number of waves that move past a certain point in one second
Frequency
Materials that allow all light to pass through.
Transparent
Let light through but scatter it.
Translucent
Materials that do not let light through (they absorb or reflect the light).
Opaque
To send (as in sound or light). It also means light passing through an object.
Transmit
The order of colours in the visible spectrum:
Red, Orange, Yellow, Green, Blue, Indigo, Violet
Light ray which hits the surface.
Incident ray
Ray which is reflected from the surface.
Reflected ray
Imaginary line drawn perpendicular to the surface.
Normal line
Angle between the incident ray and normal line.
Angle of incidence
The angle between the reflected ray and normal line
Angle of reflection
The colour of light which is refracted the least by a triangular prism.
Red
The colour of light which is refracted the most by a triangular prism.
Violet
A lens which has two sides that curve inwards.
Biconcave
A lens which has one side that curves outward.
Convex
Shadows: an object far from a light source makes a …………………….. shadow.
small
Shadows: an object close to a light source makes a …………………. shadow.
big
The law of reflection
The angle of incidence is equal to the angle of reflection.
At a cricket match we see the bat hit the ball before we hear the ‘crack’ because…
light travels faster than sound.
If light moves from air to glass, the light is refracted …………………………. the normal.
towards
If light moves from water to air, the light is refracted ……………………. the normal
away from
The part of the eye that transmits information from the retina to the brain.
Optic nerve
The hole in the centre of the iris that controls how much light enters the eye.
pupil
In bright light the pupil …………………… in size.
decreases
In dim light the pupil ……………………….. in size.
increases
The protective front covering of the eye.
cornea
The sensory layer at the back of the eye.
retina
When light hits a rough surface, the light is …………………………
scattered
True or False: A black object appears black because it reflects black light into your eye.
False
True or False: A white object appears white because it reflects the entire visible spectrum into your eye.
True
True or False: A red object appears red because it absorbs all the colours of light, except red, which it reflects into your eye.
True
