Question

A person has far point of eye at 200 cm.
What type of lens should be used to correct
the person's eyesight and what should be
its focal length?
O
Concave, 200 cm
Convex, 100 cm
O
Concave, 100 cm
Convex, 200 cm​

Answer 1

Answer:

look the crux lies in , we need to form the image of infinity at 200 cm only

the rays are converging beforehand,we want to converge afterwards so use concave lens

Explanation:

1. 1/v-1/u=1/f
2. put u as ♾️ and v as 200with signs
3. use some ink and paper,if u know what I mean