Explain the terms given below related to lens 1)centre of curvature 2) normal 3)pole 4) focal point 5) focal length
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Answer.
(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
(1) the center of curvature of a curve is found at a point that is at a distance from the curve equal to the radius of curvature lying on the normal vector.
(2)Normal is the centre of the lens.
(3)The point where principal axis meets the surface.
(4)The focal point of a lens or mirror is the point in space where parallel light rays meet after passing through the lens or bouncing off the mirror. A "perfect" lens or mirror would send all light rays through one focal point, which would result in the clearest image.
(5)It is the distance between lens and the focus