Eye

Question 1

What happens to the eye in bright light

Answer 1

-Circular muscle- contract
-radial muscle-relax
-Iris- widens
-pupil- constricts
-light- less

Question 2

What happens in dim light

Answer 2

-Circular msucle- relax
Radial- constricts
-Iris- marrows
Pupil- dilates
-Light entering- more

Question 3

What happens when light rays enter from a distant object

Answer 3

-light rays are virtually paralle- require little refraction to focus on retina
-ciliary muscles relax, forming a winder ring, causing them to pull of the suspensory ligaments, which are under tension from the vitrous humour- making them taut
-ligamnets in turn pull on the lens- stretch it and makes it flatter
-this flatter less convex shape requires less refraction

Question 4

What happens to light rays from a near object

Answer 4

-light rays are diverging- spreading out- require more refraction to focus onto the retina
-ciliary muscles contract, forming a winder ring, which in turn takes the tension off the suspensory ligaments, causing thm to slack
-the lens is not stretched, as it is elastic, so reverts to its natural more fatter shape
-this fatter, more convex shape requires more refractipn