Question

A man can read a book kept at a distance of 20 em. If book kept at 30 em distance,
man uses spectacles to read this book. Calculate-i) focal length of used lens,
m nature of lens, (ii) clarify the defect of vision by drawliny rag diagram.​

Answer 1

Answer:

f=50cm

Hence a concave lens of focal length 50cm is used.

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Answer 2

Answer:

f = 50.................