Question

If doctor advised to use 5d lens then it's focal length is how much

Answer 1

Answer:

20cm

Explanation:

Answer 2

Focal length of lens is 0.2m

•Focal length is calculated by the formula - 1/Power of lens.

•Focal length = 1/5 = 0.2 m.

•There are two types of conditions, namely nearsightedness and farsightedness.

•Nearsightedness is a condition when concave lens are used to rectify the image.

•In this, image forms before retina.

•The focal length is negative for this condition.

•Farsightedness is a condition where convex lens corrects the problem.

•In this, image forms behind the retina.

•The focal length is positive for this condition.