Question

Define center of curvature, principal axis, optical center, aperture, focus, focal length for a lens.

Answer 1

Hint : tTo solve this question we have to know about lens. a piece of glass or other transparent material with curved sides for concentrating or dispersing light rays, used singly (as in a magnifying glass) or with other lenses (as in a telescope).

Complete Step By Step Answer:
(a) Centre of curvature: Centre of curvature of a spherical mirror is the Centre of the hollow sphere of a glass of which the mirror is a part.
(b) Radius of curvature: Radius of curvature of a spherical mirror is the radius of the hollow sphere of glass of which the mirror is a part.
(c) Pole: The Centre of a spherical mirror is called its pole.
(d) Principal axis: The straight line passing through the Centre of curvature and pole of a spherical mirror is called its principal axis.
(e) Aperture: The portion of a mirror from which the reflection of light actually takes place is called Aperture.

Note :
We know that, A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (elements), usually arranged along a common axis. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. We have to keep this in our mind.