human eye

Question 1

regular reflection

Answer 1

when a parallel beam of light strikes a smooth surface and gets reflected back as a parallel beam of light

Question 2

diffused reflection

Answer 2

when a parallel beam of light strikes a rough surface and gets reflected back in various directions

Question 3

sclera

Answer 3

the outermost covering of the eye. protects the inner delicate parts of the eyes.

Question 4

choroid

Answer 4

dark grey pigmented layer attached to the sclera on the inner side is richly supplied with blood vessels. darkens the eye from inside to prevent and internal reflection

Question 5

cornea

Answer 5

infront of the eye. it allows light to enter the eyes.

Question 6

retina

Answer 6

has a large numbers of cells namely 2 types called rods and cones. rods are sensitive to dim light lights. cones are sensitive to bright lights.

Question 7

iris and pupil

Answer 7

iris gives colour to the eye. the iris has a central circular aperture called pupil. iris controls the amount of light that enters in the eyes by adjusting the size of pupil. if lights are dim iris expands the pupil to enter more light and vice versa.

Question 8

crystalline lens

Answer 8

it is a transparent crystalline double convex lens situated just behind the iris. it helps the the ciliary muscles.

Question 9

suspensory ligaments

Answer 9

along with ciliary muscles it is also attached to the lens.

Question 10

ciliary muscles

Answer 10

muscles which hold eye lens in proper place. the focal length of the eye can be changed according to the distance of the object in-front of the eye. when ciliary muscles contract eye lens becomes thick and its focal length decreases. when ciliary muscles are relaxed the eye lens becomes thin and its focal length increases.

Question 11

optic nerve

Answer 11

consists of about 1 million seperate nerve fibres that connects rods and cones to the brain. it send the information to the brain in form of electric signals.

Question 12

aqueous humour

Answer 12

the space between the cornea and the eye lens is filled with clear watery liquid

Question 13

vitreous liquid

Answer 13

space between eye lens and retina is filled with a liquid called vitreous liquid. it keeps the eye wet.

Question 14

blind spot

Answer 14

at the junction of optic nerve and retina there are no sensory cells (rods and cones). so no vision is possible there.