HEALTH Light And Sight Flashcards
What is refraction?
The bending of light/change of speed as it passes from one material to another.
Light is focused by the ____ and the _____. Most of the refraction takes place at the _____. The ____ changes shape and allows the eye focus on objects at different distances.
Light is focused by the CORNEA and the LENS. Most of the refraction takes place at the CORNEA. The LENS changes shape and allows the eye focus on objects at different distances.
When light passes from air into glass, light bends _____ the normal and when it passes from glass to air it bends _____ from the normal.
When light passes from air into glass, light bends TOWARDS the normal and when it passes from glass to air it bends AWAY the normal.
Concave
Bends in
Convex
Bends out
How do convex affect light?
Brings the light to a fous
How does concave lens affect light?
Spreads it out
How is the image formed on the retina different to the real object?
Image is formed upside down, back to front and smaller
What is focal length?
The distance between a lens and the point where parallel rays of light are brought to a focus.
Describe an experiment to measure focal length
Put e lens i front of a screen and move e lens until a sharp image if distance object is obtained on the screen. Measure the distance from the lens to the screen and this is the focal length,
Short sighted people can’t focus on _____ objects clearly.
Distant
Long sighted people can’t focus on _____ objects clearly.
Close
What type of lens corrects short sighted vision?
Concave
What type of lens corrects long sighted vision?
Convex
What type of light do fibre optic transmit?
Cold light (no heat is transmitted)