Large and is given by the ratio of the size of the image seen through a compound Magnifying power of a compound microscope is very The objective and the eyepiece can be varied to get a clear image. The two tubes areĪrranged so that they have a common principal axis. The other lens has a little larger focal lengthĪnd is fixed at the end of another tube. One of the lenses has a short focal lengthĪnd is fitted at the end of a tube. (2) Compound Microscope: A compound microscope essentiallyĬonsists of two convex lenses. Is magnification D the least distance of distinct visionĪnd f the focal length of lens. Given by the formula m = 1 + (D/f), where m The Magnifying power of a simple microscope is Upright virtual and enlarged image on the same side of object. Principal focus and the optical center of a convex lens, it forms an The principal that when an object is placed between first (1) Simple Microscope: Simple microscope uses (1) Simple Microscopes (2) Compound Microscopes. The defect can beĬorrected by using a convex lens of appropriate focal length in front of The power of accommodation, thus, reduces.ĭistant objects can still be seen clearly since theĬiliary muscles are relaxed while looking at distant objects. Thus the image is formed a little closer. The convex lens converges the incoming rays and This defect is corrected by using a convex lens Slightly behind the retina when the ciliary muscles are relaxed, so the imageĬannot be seen clearly. The eye lens and the retina is less, the image of a distant object is formed TheĬoncave lens diverges the incoming rays and thus the image is formed a little further away.Īn elongated eyeball leads to hypermetropia. This defect is corrected by using a concave lens in front of the eye. Of the eyeball due to increase of the distance between the eye lensĪnd the retina, the image of a distant object is notįormed on the retina with relaxed ciliary muscles, but infront of the retina. (a) Myopia: It arises due to slight elongation (a) Myopia (b) Hypermetropia (c) Presbyopia. Slightly elongated or flattened eyeballs. Vision Defects: Some of the people have.
The property of theĮye lens of being able to adjust its focal length for the objects atĭifferent distances is called the power of accommodation.Ĭolour blindness of the eyes in some people is because of the absence of Length of the eye lens must change in accordance with the distance of That means, the image distance is fixed, hence the focal The image is always produced on the retina no matter Thing we see with the most remarkable optical instrument known – the eye. Human Eye and its Characteristics: Light is the only.Or analyze light waves to determine one of That are used to processes light waves to enhance an image for viewing, Optical Instruments: Optical instruments are devices.