A student finds the writing on the blackboard as blurred and unclear when sitting on the last desk in the classroom. He however, sees it clearly when sitting on the front desk at an approximate distance of 2 m from the blackboard.
Draw ray diagrams to illustrate the formation of image of the blackboard writing by his eye-lens when he is seated at the (i) last desk (ii) front desk.
Name the kind of lens that would help him to see clearly even when he is seated at the last desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.
(i) When the student is seated at the last desk, the image of the blackboard writing is formed in front of the retina.
(ii) When the student is seated at the front desk, the image is formed at the retina.
The student is suffering from myopia. This defect can be corrected by using concave lens of desired focal length.
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