The focal length of the eye lens increases when eye muscles
(a) are relaxed and lens becomes thinner
(b) contract and lens becomes thicker
(c) are relaxed and lens becomes thicker
(d) contract and lens becomes thinner
When eye muscles are relaxed and become thinner, the focal length of the eye lens increases.
Similarly when eye muscles are contracted, focal length decreases.
The sharp image of the distant object is formed at the retina by adjusting the focal length of eyelens. This enables us to focus accurately on distant objects.
Therefore option (a) is correct