Question
Question: A man cannot see clearly the objects beyond a distance of 20 cm from his eyes. To see distant object...
A man cannot see clearly the objects beyond a distance of 20 cm from his eyes. To see distant objects clearly he must use which kind of lenses and of what focal length
A
100 cm convex
B
100 cm concave
C
20 cm convex
D
20 cm concave
Answer
20 cm concave
Explanation
Solution
f = – (defected far point)
= – 20 cm