List of top Science Questions on The Human Eye asked in CBSE Class X

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:

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:

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.

(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.

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.

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 –

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

Why is a normal eye not able to see clearly the objects placed closer than 25 cm?

What happens to the image distance in the eye when we increase the distance of an object from the eye?

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

The least distance of distinct vision for a young adult with normal vision is about

The human eye forms the image of an object at its

The human eye can focus objects at different distances by adjusting the focal length of the eye lens. This is due to