Question

Explain the following terms for a convex lens :
• Centre of curvature
• principal Axis
• Optical Centre
• Aperture
• Radius of curvature
• Principal focus
• Focal length ​

Answer 1

Explanation:

(a) Centre of curvature is the centre of the sphere of which the spherical mirror is a part. (b) Radius of curvature is the linear distance between the pole and the centre of curvature. (c) Pole is the mid point of a spherical mirror. (d) Principal axis is an imaginary line passing through the pole and the centre of curvature of a spherical mirror. (e) Principal focus is a point on the principal axis, where a beam of light, parallel to the principal axis, after reflection, either actually meets (concave) or appears to meet (convex). (f) Focal length is the linear distance between the pole and the principal axis