(1)

We know that human eye is the most valuable sense organ because it enables us to see this colourful world. Thus, both assertion and reason are correct and reason is the correct explanation of assertion.

(1)

Human eye works like a camera because of its lens system. Light enters the eye through a thin membrane called the cornea. It forms the transparent bulge on the front surface of the eyeball. The eye lens forms an inverted real image of the object on the retina. Thus, both assertion and reason are correct and reason is the correct explanation of assertion.

(1)

The curvature of the eye lens is modified to change the focal length. When the muscles are relaxed, the lens becomes thin. Therefore, there is an increase in the focal length. This enables us to see distant objects clearly. This modification in lens is done by ciliary muscles. Thus, both assertion and reason are correct and reason is the correct explanation of assertion.

(2)

The person cannot see the objects distinctly and comfortably because of accommodation. The vision becomes blurred due to the refractive defects of the eye. Therefore, the given assertion is correct but reason is not the correct explanation of assertion.

(4)

Myopia is known as near-sightedness and hypermetropia is known as far-sightedness. The image of a distant object is formed in front of the retina in myopia. Thus, assertion is false but reason is true.

(3)

Sometimes, the crystalline lens of people at old age becomes milky and cloudy. This condition is called cataract. It causes partial or complete loss of vision. The eyeball is spherical in shape, not elliptical. Thus, the given assertion is true and reason is false.

(1)

A person with myopia can see nearby objects clearly but cannot see distant objects distinctly. A person with this defect may see clearly up to a distance of a few metres. In a myopic eye, the image of a distant object is formed in front of the retina but not at the retina itself. This defect may arise due to excessive curvature of the eye lens. Thus, both assertion and reason are correct and reason is the correct explanation of assertion.

(4)

The power of accommodation of the eye usually decreases with ageing, and presbyopia arises due to the gradual weakening of the ciliary muscles. Thus, assertion is false but reason is true.

(2)

The refractive defects can be corrected by contact lenses, and the eye lens is composed of fibrous jelly-like material. Thus, both assertion and reason are correct but the reason is not the correct explanation of assertion.

(2)

The farthest and the nearest point of the eye is based on the distance at which the object is placed. Thus, both assertion and reason are correct but the reason is not the correct explanation of assertion.