Question

Define the following for convex lens. i) Optical centre ii) Aperture iii) Principal focus iv) focal length ​

Answer 1

Answer:

Principal focus is the point at which a beam of light that is parallel to principal axis will converge/diverges after refraction. Focal length is the distance between the optical center and principal focus of the lens.

Answer 2

Answer:-

(i) Optical Center :- The central point of the lens is called its optical centre . It is incident towards the optical centre passes almost without any deviation through the lens .

(ii) Aperture:- The circular area that determines the amount of light falling on a mirror or a lens is its aperture.

(iii) Principal Focus:- It is the point where the beam of rays parallel to principal axis seems like diverge or converge from a point on the principal axis.

(iv) Focal Length:- The distance between the pole and the focus is called it's focal length. It 8s denoted by f.