What is focal length?
Ans: the distance between the pole and focal point.
What is the relationship between the radius of curvature and focal length?
Ans: R=2f
What is myopia?
When a person can see near things clearly but can't see distant objects is called myopia.
Which lens do we use to correct myopia?
Concave lens
What is the cause of myopia?
I. Elongation of eyeball
II. Increase the curvature of the lens