Light Flashcards
How does light travel
In straight lines, through a vacuum at the speed of light (3x10^8)
What is the speed of light
3x10^8m/s (300 000 000m/s)
Do different colours have different wave lengths and frequencies
Yes
What colours transmit light
clear surfaces
What colours absorb light
Dark colours
What colours reflect light
Light colours
Name the primary colours of light
Red, blue and green
How do filters work
Coloured filters absorb certain wavelengths of colour and transmit the other wavelengths. These other wave lengths are reflected off the objects allowing them to become visible. For example, a blue flower absorbs all other colours of different wavelengths except blue which is reflected.
State the Law of Reflection
When light is reflected, the angle of incidence is equal to the angle of reflection
Define luminous
An object that gives out light (light bulb)
Define non-luminous
An object that does not give out light (comb)
Do luminous objects reflect or emit
Emit
Do non- luminous objects reflect or emit
Reflect
Describe refraction in terms of the movement of light between different mediums
Light moving through air travels at a constant speed (the speed of light) in a straight line. When light travels from air into another medium is changes direction and slows down
Define refraction
The bending of light as it moves from one transparent object to another
State the 5 ways that light behaves
Define dispersion
The separation of visible light into different colours (for example white light passes through a transparent object and splits into a spectrum of different colours)
Describe the shape of a concave lens
Shaped inwards at the centre and outwards at the edges
Describe the shape of a convex lens
Curves outwards
Is a concave lens a diverging or converging lens
Diverging - where the light diverges outwards
Is a convex lens a diverging or converging lens
Converging - where the light converges inwards to meet a focal point
What are rays of light called?
Photons
How do mirrors produce images of objects
When photons coming from an object strike a smooth surface (mirror) they bounce back at the same angle (law of reflection).
What happens to light when it hits a rough surface
When photons reach a rough surface, the light rays scatter in all directions causing diffusion
