(i) defect of vision and also

A students is unable to see clearly the words written on the blackboard placed at a distance if approximately 4m from him. Name the defect of vision the boy is suffering from. Explain the method of correcting this defect. Draw ray diagram for the :
(i) defect of vision and also.
(ii) for its correction.

As the student is not able to clearly see the words written on the blackboard that is at a distance of approximately 4 m from him, the student is suffering from the defect called myopia or near-sightedness. A myopic eye has its far point nearer than infinity. It forms the image of a distant object in front of its retina. To correct a myopic eye, concave lens of a suitable focal length is used. The image is allowed to form at the retina by using a concave lens of suitable power.

  1. A myopic eye
  2. Correction of myopia using concave lens