The Human Eye and the Colourful World

The distance of distinct vision for a normal eye is

• 2.5 cm

• 25 cm

• 2.5 m

• 25 m.

The focal length of the eye lens increases when eye muscles

• are relaxed and lens becomes thinner

• contract and lens becomes thicker

• are relaxed and lens becomes thicker

• contract and lens becomes thinner

The ability of eye to focus the near as well as distant objects is called

• flexibility

• astigmatism

• power of accomodation

• myopia.

When light rays enter the eye, most of the refraction occurs at the

• crystalline lens

• outer surface of the cornea

• iris

• pupil

The image distance from the eye lens in the normal eye when we increase the distance of an object from the eye:

• increases

• decreases

• remains unchanged

• depends on the size of the eyeball

A man cannot see objects distinctly at a distance greater than 3 metres. He is suffering from

• astigmatism

• myopia

• hypermetropia

• distortion.

A man is unable to see objects distinctly at a distance less than 1 metre. He is suffering from

• astigmatism

• myopia

• distortion

• hypermetropia.

Myopia occurs due to

• increase in the focal length of the eye lens

• decrease in focal length of the eye lens

• contraction of the eye ball

• decrease in distance between the retina and the eye lens.

A myopic eye is corrected by using

• cylindrical lens

• convex lens

• concave lens

• anastigmat lens.

Which of the following statement is correct?

• A person with myopia can see distant objects clearly

• A person with hypermetropia can see nearby objects clearly

• A person with myopia can see nearby objects clearly

• A person with hypermetropia cannot see distant object clearly