List of top Science Questions on The Human Eye

The sky appears dark to passengers flying at very high altitude

What is a rainbow? 'We see a rainbow in the sky only after the rainfall.' Why?

A person must hold reading material at a distance greater than 25 cm for clear vision.
(i) What is the name of this visual defect?
(ii) Draw a ray diagram to show its correction.

A person uses lenses of power -0.5 D in his spectacles for the correction of his vision. (a) Name the defect of vision the person is suffering from.

The lens system of human eye forms an image on a light sensitive screen, which is called as :

Study the diagram given below and answer the questions that follow:

(i) Name the defect of vision represented in the diagram. Give reason for your answer.
(ii) List two causes of this defect.
(iii) With the help of a diagram show how this defect of vision is corrected.

Consider the following statements in the context of human eye:
(a) The diameter of the eye ball is about 2.3 cm.
(b) Iris is a dark muscular diaphragm that controls the size of the pupil.
(c) Most of the refraction for the light rays entering the eye occurs at the crystalline lens.
(d) While focusing on the objects at different distances the distance between the crystalline lens and the retina is adjusted by ciliary muscles.
The correct statements are –

Assertion (A): Myopic eye cannot see distant objects distinctly.
Reason (R): For the correction of myopia converging lenses of appropriate power are prescribed by eye-surgeons.

(a) Define the term power of accommodation of human eye. Write the name of the part of eye which plays a major role in the process of accommodation and explain what happens when human eye focuses (i) nearby objects and (ii) distant objects.
OR
(b) Draw a ray diagram to show the formation of a rainbow in the sky. On this diagram mark A – where dispersion of light occurs, B – where internal reflection of light occurs and C – where refraction of light occurs. List two necessary conditions to observe a rainbow.

Study the diagram given below and answer the questions that follow :

When do we say that a particular person is suffering from hypermetropia? List two causes of this defect. Name the type of lens used to correct this defect.

Consider the following statements:

1. Ciliary muscles adjust for changing the intensity of light entering the eye.
2. Myopic eye can be corrected by converging lenses of suitable power.
3. The function of the pupil is to regulate the quantity of light entering the eye.
4. When ciliary muscles are completely relaxed, the focal length of the eye lens is maximum.

The correct statements are:

The amount of light entering in the eye is controlled by:

Explain the power of accommodation of the eye. Draw a ray diagram for image formation by a convex lens when (a) the object is at a distance of 2f, (b) the object is in between 2f and infinity.

A person having normal eye can clearly see an object, if the distance of the object from the eye is:

A person is unable to see distant objects clearly. Defect in his eyes will be:

A person suffering from short-sightedness can see up to 100 meters. Calculate the nature and the focal length of the lens in order to correct this defect so that he can see objects at infinity hence correct vision. Also, draw the ray diagram.