(i) Ravi kept a book at a distance of 10 cm from the eyes of his friend Hari. Hari is not able to read anything written on the book. Explain why? (ii) A lens of focal length 5.0 cm is being used by a student in the laboratory as a magnifying glass. His least distance of distinct vision is 25 cm. What magnification is the student getting?

(i) Ravi kept a book at a distance of 10 cm from the eyes of his frien

1.	(i) Ravi kept a book at a distance of 10 cm from the eyes of his friend Hari. Hari is not able to read anything written on the book. Explain why? (ii) A lens of focal length 5.0 cm is being used by a student in the laboratory as a magnifying glass. His least distance of distinct vision is 25 cm. What magnification is the student getting?
Answer» SOLUTION :(i) Because least distance of distinct VISION is 25 cm, and book is kept at a distance of 10 cm. (ii) `U=?, v=-25cm, f=5cm`. `(1)/(f)=(1)/(v)-(1)/(u)` `(1)/(5)=(1)/((-25))-(1)/(u)` `(1)/(u)=(1)/((-25))-(1)/(5)` `u=(-25)/(6)` `m=(v)/(u)` `m=(-25)xx(6)/(-25)` `m=6`