🔥HUMAN EYE QUICK REVISION 🔥 скачать в хорошем качестве

🔥HUMAN EYE QUICK REVISION 🔥

For clas10, , cbse and other state board, very easy way explain math and science important mcq maths class 10 2024 kdrama study motivation short video reasoning classes by samresh sir arabic islamic lectures with english subtitles the viral maths adda247 similar triangles class 10 maths world class 10th maths statistics one short video class 10 up board math mcq sample paper discussion class 10 2024 jamia 9th class entrance exam date 2024 innovative gyan class 10 #science #eyes #physics #ncert Human Eye We are able to see things with the help of our eyes. The Eye is one of the most important sense organs. Let us see the structure of our eye. The Shape of the eye is roughly spherical with an average diameter of around 2.3 cm. The outer part of the eye is quite tough and white in colour. This white part of the eye is known as sclera. The transparent, front outer covering of the eye is known as the cornea. Behind the cornea, there is a colored membrane known as the Iris. It regulates the amount of light entering the eye. It also gives colour to the eye. In the iris, there is a variable sized, black. circular opening known as the pupil. Its size is controlled by the iris. It appears to be black in colour because most of the light entering it is absorbed by the tissues, which are present in the pupil. The size of the pupil depends on the brightness of light. It opens and closes in order to regulate and control the amount of light entering the eye. When we enter a dimly lit room, it takes the iris some time to expand the pupil to allow more light to enter the eye. For this reason, it takes us a few seconds to clearly see objects in a dimly lit room Ciliary body Iris Cornea Pupil Aqueous chamber Vitreous chamber Sclera Fovea Retina Lens Blind spot -Choroid Optic nerve Behind the pupil there is a lens which is thicker at the centre. It is made up of living cells. Two Ciliary muscles hold the lens within the eye-ball. The eye lens being convex in nature converges the light rays' incident on it. Hence, it focuses the light falling on it on a thin layer of nerve cells called the retina. The retina is made up of a large number of nerve cells. To see the nearby objects clearly, the focal length of the lens should be shorter. For this, the ciliary muscles contract to increase the curvature and thereby decrease the focal length of the lens. Hence, the lens becomes thick. This enables you to see the nearby objects clearly. The ability of the eye lens to adjust its focal length accordingly as the object distances is called power of accommodation. The minimum distance of the object by which clear distinct image can be obtained on the retina is called least distance of distinct vision. It is equal to 25 cm for a normal eye. The focal length of the eye lens cannot be decreased below this minimum limit of object distance. Let us see what happens when an object is at a distance less than 25 cm from the eye lens. The far point of a normal eye is infinity. It is the farthest point up to which the eye can see objects clearly. The range of vision of a normal eye is from 25 cm to infinity. Have you ever thought why animals' eyes are positioned on their heads?