HOW DO WE SEE? LENSES/IMAGING

Question 1

HOW DO WE SEE?

Answer 1

Light that reflects off of objects enters our eye, and that is how we see, we see colour in the same way, colour that reflects off of objects we are able to detect. Colours that are absorbed by the object however, we cannot see.
Light enters the eye via the pupil. When the light hits the back of the eye, it hits the retina. The retina contains photoreceptors (rods and cones). This transmits signals to the brain to allow for visual processing.
→ however, because of the lens, light is gathered as a focal point on the retina, so the image is flipped to be upside down, however visual processing in the brain reflips the image and gets rid of any other distortions.

Question 2

CHARACTERISTICS OF A LENS

Answer 2

A lens is a piece of glass or other transparents material that is shaped in a way that either causes incident rays to either
1) Come together into one focal point
Or
2)appear to be diverging from a point

Question 3

TYPES OF LENSES

Answer 3

→ convex lenses: are thicker on the edges than in the center, causes light to converge

Question 4

POWER OF LENSES AND FOCAL LENGTH

Answer 4

Focal length: is the distance between the focal point and the center of the lens, represented by F (always in meters!)
Power (P) of the lens is the inverse of the focal length. Is is calculated by 1/f