Human eye

In the following dia. showing dispersion of white light by a glass prism, the colours p and q respectively are :

• Red and violet

• violet and red

• red and blue

• orange and green

In human eye the part which allows light to enter into the eye is:

• Retina

• Pupil

• Eye lens

• Cornea

The phenomena of light involved in the formation of rainbow are :

• Refraction, dispersion and scattering

• refraction , reflection and dispersion

• refraction , dispersion and internal reflection

• reflection, dispersion and total internal reflection

The change in the focal length of an eye lens in human beings is caused by the action of

• optic nerves

• ciliary muscles

• retina

• cornea

Name the phenomenon of light due to which the path of beam of light becomes visible when it enters a smoke filled room through a small hole

• scattering

• tyndall effect

• dispersion

• total internal reflection

when a beam of white light passes through a region having very fine dust particle, the colour of light mainly scattered in that region

• red

• orange

• blue

• yellow

Which of the following statements about the retina is true?

• A) It is the outermost layer of the eye.

• B) It is responsible for detecting color and fine details.

• C) It produces tears that lubricate the eye.

• D) It controls the amount of light that enters the eye

 Assertion: the sky looks dark for an astronaut.

Reason: in space , all colour light travel with the same speed and together give the effect of dark colour.

• a) Both A and R are true, and R is the correct explanation of A.

• b) Both A and R are true, and R is not the correct explanation of A.

• c) A is true, but R is false.

• d) A is false, but R is true.

Assertion: the sun light has to cover a larger distance when it is overhead.

Reason : the sun appears white at noon

• a) Both A and R are true, and R is the correct explanation of A.

• b) Both A and R are true, and R is not the correct explanation of A.

• c) A is true, but R is false.

• d) A is false, but R is true

A person can see clearly objects lying between 25 cm and 2m from his eye. His vision can be corrected by using spectacles of power what?

• -0.5 D

• 0.5 D

• -2 D

• 2D