Working of an Eye
Working of an Eye
Working Of Eye or Light Control:: Light rays after reflecting from the object enter the eye first through the cornea, which is a clear dome in the front of the eye.The light then progresses through the pupil and than passes through the crystalline lens, which is located immediately behind the iris and pupil.The iris controls the diameter of the pupil automatically. Initially, the light waves are bent or converged first by the cornea , and then by the crystalline lens. In dim light, the iris widens (or dilates) the pupil to admit more light into the eye. In bright light, it contracts the pupil so that less light goes in. With in the layer of the retina, light impulses are changed into electrical signals, then sent to the brain through the optic nerves. In this way, the iris-pupil combination controls the amount of light into the eye to ensure that the best-possible image is formed under different light conditions.
Between the cornea and the lens lies a muscular diaphragm called the iris. The round, coloured part that we see in the eye is the iris.Iris gives distinct colour to the eye. When we say that the person has green eyes, we actually refer to the colour of the iris. It has a small opening called the pupil, through which light enters the eye. The iris controls the diameter of the pupil automatically. In dim light, the iris widens (or dilates) the pupil to admit more light into the eye. In bright light, it contracts the pupil so that less light goes in. In this way, the iris-pupil combination controls the amount of light into the eye to ensure that the best-possible image is formed under different light conditions.
Persistance Of Vision: The image of the object formed on the retina of the eye does not disappear immediately. Even if the object is removed, the image of any object seen will last for one sixteenth of a second on the retina. This eye sensation that lasts for a period of time is called visual persistence. So, if still images of a moving object are flashed on the eye at a rate faster than 16 per second, then the eye perceives that object is moving. That's why a series of fast-moving still pictures can create an illusion of movement. This property of of vision is used in cinematography.
A human eye employs a ______________ lens to form ___________ images. | |||
| Right Option : A | |||
| View Explanation | |||
A ray entering the eye undergoes refraction at ______________________. | |||
| Right Option : D | |||
| View Explanation | |||
Which of the following are correct : (a) In dim light, the iris widens the pupil to admit more light into the eye. (b) In bright light, it contracts the pupil so that less light goes in. (c) In bright light, it widens the pupil so that less light goes in. | |||
| Right Option : A | |||
| View Explanation | |||
Students / Parents Reviews [10]
My experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
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Barkha Arora
10thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thAbhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
Om Umang
10thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
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Prisha Gupta
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Hiya Gupta
8thOne of the best institutes to develope a child interest in studies.Provides SST and English knowledge also unlike other institutes. Teachers are co operative and friendly online tests andPPT develope practical knowledge also.
