Light Flashcards
(12 cards)
What are luminous sources?
Objects that create light.
How does light travel?
In straight lines.
Light waves travel through transparent objects but not opaque ones.
Shadows form because light doesn’t go through opaque.
Translucent objects show a glow of light.
What is light transmission?
Transparent materials lets light pass straight through. They transmit light
What is light absorption?
Opaque surfaces can absorb light. Black surfaces absorb light v well and reflect little. This is why they look so dark
What is reflection?
Light rays are scattered by rough surfaces so reflection can not be seen.
A plane or flat mirror reflects light evenly.
What is the rule of reflection?
Angle of incidence = angle of reflection.
How does a mirror work?
When light shines on object viewed in mirror, rays are reflected into the eye.
The image is the same size and distance from mirror but right becomes left and left becomes right.
What is refraction?
When light hits something transparent it changes direction.
Light refracts where two substances meet.
Light slows down through glass and bends towards the normal.
When it leaves the glass it speeds up and bends away from normal.
What is colour?
Explain how it works?
White light is a mixture of colours.
White light can be split using a prism.
This is called dispersion.
Dispersion gives a spectrum of 7 colours.
A spectrum and a rainbow both have 7 colours - what are they?
Red Orange Yellow Green Blue Indigo Violet
How is a rainbow produced?
When water droplets in the air refracts sun light.
How are different colours made?
By mixing light of the 3 primary colours - red, green and blue.
We see colours because objects don’t reflect all colours in light.
Coloured light can be made by a filter, a red filter lets through red but absorbs other colours.
White objects reflect all colours.
Black objects absorb all colours.
