# Convex lens and focal length

1)Why when a convex lens having radius of curvature R, focal length f and refractive index μ is

bisected horizontally along the principal axis its focal length remains the same, whereas when

it is bisected vertically focal length becomes 2f? Does the same thing happens in the case of

concave lens too?

tiny-tim
Homework Helper
Hi Alche!

Tell us what you think, and then we'll comment.

Tell us what you think, and then we'll comment.

Well, I think when we bisect the convex lens vertically its radius of curvature becomes R/2 so the focal length becomes 2f.

And I am sure the same things happens with concave lens too :tongue:

tiny-tim