Question

a person cannot see the object placed at a distance more than 40cm.he is advised to use lens of power

​

Answer 1

The person cannot see an object placed at distance greater than 40cm. So he suffers from Myopia which implies he uses concave lens.

Therefore his far point is 40cm.

Since light from object falls on far point , the far point and focus lie at the same point.

So focal length is 40cm = 0.4 m

Power = 1 / focal length in m

Power = 1 / 0.4 = +2.5 D

Since he uses concave lens Power is -ve

So, Power = -2.5D

Please mark it the brainliest answer.

Thank You.