Name the four common defects of vision and state the cause of each defect. A person cannot see distinctly objects placed beyond 2 metres. State the nature and focal length of the lens which could be used to correct this defect.
OR
(a) Describe with diagram an experiment to show that a force is exerted on a current carrying conductor when placed perpendicular in a magnetic field.
(b) State the rule to find the direction of the force exerted on a current carrying conductor in a magnetic field.
Answers
Myopia: (nearsightedness) This is a defect of vision in which far objects appear blurred but near objects are seen clearly. The image is focused in front of the retina rather than on it usually because the eyeball is too long or the refractive power of the eye’s lens too strong
Hyperopia: (farsightedness) This is a defect of vision in which there is difficulty with near vision but far objects can be seen easily. The image is focused behind the retina rather than upon it. This occurs when the eyeball is too short or the refractive power of the lens is too weak
Astigmatism: This defect is when the light rays do not all come to a single focal point on the retina, instead some focus on the retina and some focus in front of or behind it. This is usually caused by a non-uniform curvature of the cornea.
PLEASE MARK AS THE BRAINLIEST ANSWER