Optics Flashcards
Non-luminous
Does not produces its own light but reflects light in order to be seen. (eg: The Moon)
Luminous
Produces its own light (eg: The Sun)
Transparent Object
Fully allows light to pass through (eg: clear glass)
Translucent Object
Partially allows light to pass through (eg: bathroom window glass)
Opaque Object
Does not allow light to pass through (eg: Metal)
Scattering of Light
To have a clear sight the image must be …?
Focused on the retina.
A thick lens = shorter or longer focal length?
Shorter
A thin lens = shorter or longer wavelength?
Longer
To cater for viewing far objects and close objects what doe dthe lens do?
It changes shape between thick and thin.
If the lens is unable to change shape to focus on a far or near object, then what happens to the image?
It becomes blurred
Short sighted
Can’t see far objects
Long sighted
Can’t see near objects
What lens is needed to fix short sighted-ness?
A concave lens
Why is a concave lens needed to fix short sighted-ness?
Because before the light reaches the eye it diverges the rays so before it enters the eye it’s more spread out, so it doesn’t bend before it reaches the retina.
What lens is needed to fix longsightedness?
Convex lens
Why is a convex lens needed to fix longsightedness?
Because a convex lens converges the light before it reaches the eye, so when it goes into the eye it has already begun bending and can help the eye do it, so it doesn’t go past the retina.
What does the iris do?
It controls the diameter and size of the pupil and the amount of light that reaches the retina.
What does the cornea do?
Covers the iris and pupil and helps to keep the eye clean from dirt and germs.
What does the pupil do?
Controls the amount of light reaching the retina by enlarging or reducing its size.
What does the lens do?
Focuses the image by bending the light to hit the retina correctly. (Refraction) it changes shape to change the focal distance of the eye so it can focus on objects at different distances.
What does the vitreous gel do?
It’s a gel that fill most of the eyeball. It enables the eye to hold its round shape and holds some parts of the eye in place, it stops the eye from collapsing.
What does the optic nerve do?
Carries signals from the retina to the brain so it can interpret them.
What does the retina do?
Receives the image seen through the eye, upside down. Then it sends it to the brain via the optic nerve where it is put straight
Do convex lens converge or diverge?
Converge
Do concave lens converge or diverge?
Diverge
What is the numerical form of 1 x 10m to the power of -2?
0.01m
What appears to have happened to your foot when you look at in while in the swimming pool?
Your foot looks closer/higher than it really is
