Light Flashcards
What is Light?
Light is a transfer of energy from one store of energy to another.
What and how does light travel in?
Light travels in straight lines. Light rays travels until it strikes a non-transparent object.
What do light rays do?
Light rays show the direction light moves.
Why does the further away the source of light is make it harder to see the light?
Light spreads out so less of it reaches your eye.
Transmitted - transparent material/translucent material
Light hits and passes through
Absorbed - opaque material
Light hits and stops
Reflected or scattered - reflective material
Light hits and bounces off
What is the pupil?
The pupil is a hole that light can go through
What does the back of the eye do?
The back of the eye detects light
What do luminous objects do?
Luminous objects give off light. We can see luminous objects when the light emitted from the enters our eye.
What do non-luminous objects not do?
Non-luminous objects do not give off light.
Law of reflection
Angle of incidence=angle of reflection
Refraction
Refraction is the change in direction of a wave when it changes speed. Typically when it moves from one medium to another. If the waves slows down in the new material it will bend towards the normal. If the wave is faster in the new medium it will bend away from the normal.
What is the critical angle?
The critical angle is when the light ray switches from refracting to reflecting. If the angle to the normal in 42° or above it will reflect if it is lower then it will refract
How do our eyes detect light?
Our eyes only have sensors to detect red, blue and green light. All other colours are perceived as mixtures of these.