How does pupil work? What is persistence of vision and power of accommodation? [5 MARKS]
How does pupil work? What is persistence of vision and power of accommodation? [5 MARKS]
Each point: 1 Mark
1. Consider an example: when we come out into bright light after watching a movie in a dark theater, our eyes get closed. And when we enter the hall from the bright light, we won't be able to see and after some time we would be able to see.
2. Here the pupil of the eye provides a variable aperture, whose size is controlled by iris.
a) When the light is bright: Iris contracts the pupil, so that less light enters the eye.
b) When the light is dim: Iris expands the pupil, so that more light enters the eye.
3. Pupil opens completely, when iris is relaxed.
4. Persistence of vision: It is the time for which the sensation of an object or the image of an object continues in the eye. It is about 1/16th of a second.
5. Power of accommodation: The ability of eye lens to adjust it's focal length with the help of ciliary muscles is called power of accommodation. This helps the eye to see objects at different distances distinctly.
Each point: 1 Mark
1. Consider an example: when we come out into bright light after watching a movie in a dark theater, our eyes get closed. And when we enter the hall from the bright light, we won't be able to see and after some time we would be able to see.
2. Here the pupil of the eye provides a variable aperture, whose size is controlled by iris.
a) When the light is bright: Iris contracts the pupil, so that less light enters the eye.
b) When the light is dim: Iris expands the pupil, so that more light enters the eye.
3. Pupil opens completely, when iris is relaxed.
4. Persistence of vision: It is the time for which the sensation of an object or the image of an object continues in the eye. It is about 1/16th of a second.
5. Power of accommodation: The ability of eye lens to adjust it's focal length with the help of ciliary muscles is called power of accommodation. This helps the eye to see objects at different distances distinctly.
