Far point and near point in an Eye
Far Point and Near Point in an Eye
Far Point And Near Point: Although the power of accommodation of the eye is amazing, it has certain limitations. The focal length of the eye cannot adjust enough to form sharp images of objects kept beyond a certain point and closer than a certain point.
|
The farthest point up to which the eye can see properly is called the far point of the eye. For the normal eye, the far point is at infinity. When viewing an object at the far point, the ciliary muscles are in their most relaxed state, and the crystalline lens is at its thinnest (Figure 2.27a). Thus, the eye-lens is at its maximum focal length when looking at an object at the far point. As an object is brought closer to the eye, the ciliary muscles contract. This increases the thickness of the crystalline lens and decreases the focal length of the eye-lens. This helps to form a sharp image on the retina. At a certain point near the eye, the ciliary muscles reach the limit of their contraction. If an object is brought closer still, the ciliary muscles cannot contract further. The closest point at which an object can be placed and seen clearly is called the near point of the eye. And, the distance of the closest point at which an object can be placed and seen clearly is called the least distance of distinct vision or the least distance of clear vision |
 |
When an object is placed at the near point (that is, at a distance equal to the least distance of distinct vision), the curvature and thickness of the crystalline lens are maximum and the focal length of the eye-lens is minimum.
.The near point of the eye varies from person to person and with age. At a very young age (below 10 years), the ciliary muscles are strong and flexible, and therefore, they can contract to a great extent. At this age, the near point may be as close as 7 to 8 cm from the eye. In old age, the ciliary muscles lose flexibility, and hence, the ability to contract to the required extent is lost.As a result, the near point reaches to 1 to 2 m, or even more. However, the standard value of the least distance of distinct vision for the normal human eye is taken as 25 centimetres.
The least distance of distinct vision for a young adult with normal vision is about _________________. | |||
| Right Option : C | |||
| View Explanation | |||
The farthest point up to which the eye can see properly is called the __________________. | |||
| Right Option : B | |||
| View Explanation | |||
The least distance of distinct vision for a normal person is ______________________. | |||
| Right Option : B | |||
| View Explanation | |||
Students / Parents Reviews [20]
Abhyas academy is great place to learn. I have learnt a lot here they have finished my fear of not answering.It has created a habit of self studying in me.The teachers here are very supportive and helpful. Earlier my maths and science was good but now it has been much better than before.
Barkha Arora
10thAbhyas is good institution and a innovative institute also. It is a good platform of beginners.Due to Abhyas,he has got knoweledge about reasoning and confidence.My son has improved his vocabulary because of Abhyas.Teacher have very friendly atmosphere also.
Manish Kumar
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
10thAbhyas institute is one of the best coaching institute in the vicinity of Ambala Cantt area. The teachers of the institute are well experienced and very helpful in solving the problems of the students.The good thing of the institute is that it is providing extra classes for the students who are w...
Aman Kumar Shrivastava
10thWe started with lot of hope that Abhyas will help in better understnding of complex topics of highers classes. we are not disappointed with the progress our child has made after attending Abhyas. Though need to mention that we expected a lot more. On a scale of 1-10, we would give may be 7.
Manya
8thWhen I have not joined Abhyas Academy, my skills of solving maths problems were not clear. But, after joining it, my skills have been developed and my concepts of science and SST are very well. I also came to know about other subjects such as vedic maths and reasoning.
Sharandeep Singh
7thThird consective year,my ward is in Abhyas with nice experience of admin and transport support.Educational standard of the institute recumbent at satisfactory level. One thing would live to bring in notice that last year study books was distributed after half of the session was over,though study ...
Ayan Ghosh
8thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thIn terms of methodology I want to say that institute provides expert guidence and results oriented monitering supplements by requsite study material along with regular tests which help the students to improve their education skills.The techniques of providing education helps the students to asses...
Aman Kumar Shrivastava
10thMy 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
7thMy experience with Abhyas academy is very nice or it can be said wonderful. I have been studying here from seven class. I have been completing my journey of three years. I am tinking that I should join Abhyas Academy in tenth class as I am seeing much improvement in Maths and English
Hridey Preet
9thAbout Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thIt 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
8thMy experience with Abhyas Academy has been very good. When I was not in Abhyas whenever teacher ask questions I could not speak it confidently but when I came in Abhyas, my speaking skills developed and now I am the first one to give the answer of teachers question.
Upmanyu Sharma
7thThe experience was nice. I studied here for three years and saw a tremendous change in myself. I started liking subjects like English and SST which earlier I ran from. Extra knowledge gave me confidence to overcome competitive exams. One of the best institutes for secondary education.
Aman Kumar Shrivastava
10thMy experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
Hiya Gupta
8thBeing a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
Prisha Gupta
8thIt has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Barkha Arora
10thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thAbhyas is an institute of high repute. Yogansh has taken admission last year. It creates abilities in child to prepare for competitive exams. Students are motivated by living prizes on basis of performance in Abhyas exams. He is satisfied with institute.
