Explain the functions of the following parts of the eye: a) cornea b) iris c) pupil d) ciliary muscles e) eye-lens f) retina g) optic nerve b) If you walk from a dark room into sunlight and back again into dark room, how would your pupils alter in size? What makes this happen? c) Explain why we cannot see our seats first when we enter a darkened cinema hall from bright light but gradually they become visible.
ScienceClass 10ICSEAnswered 27 Mar 2026
Answer
- a) Cornea: The front part of an eye through which the light enters is known as
- Iris: The amount of light entering the eye is controlled by
- Pupil: The illumination in the eye is controlled by
- Ciliary muscles: This helps in contracting and relaxing the eye
- Eye lens: It helps in focusing the light to the
- Retina: It responds to the intensity of the light and colour of the objects as it has cells known as rods and
- Optic nerve: The image formed on the retina is conveyed to the brain by optic
- If we walk from the dark room into the sunlight, the pupil contracts and when we enter a dark room from sunlight, the pupil expands.
- When we enter the cinema hall from bright sunlight, we cannot see the seat clearly because when we are in bright sunlight, the pupil is small as it has contracted but when we enter the hall, the pupil expands so that more light can be accommodated.