question_answer 27)

A man with normal near point (25 cm) reads abook with small print using a magnifying glass: a thin convex lens of focal length 5 cm. (a) What is the closest and the farthestdistance at which he can read the book when viewing through the magnifying glass ? (b) What is the maximum and minimumangular magnification (magnifying power)possible using the above simple microscope ?  

Answer:

(a) To see the object at a closest distance,the image of object should be formed at theleast distance of distinct vision. Usingwe have i.e. the object is to be placed at  from the magnifying glass. Also, to see the object at the farthest point,its image must be formed at infinity, i.e. i.e. i.e. the object is to be placed at 5 cm fromthe magnifying glass. (b) Angular magnification, maximum angular magnificationand minimum angular magnification