Define the terms:Pole, Focus, Center of curvature, Aperture, Principle axis, Normal.

Asked by Dilpreet Kaur | 11th Oct, 2010, 12:00: AM

Expert Answer:

Dear Student,
1. Pole: The centre of the spherical surface of the mirror, is called the pole of the mirror. It lies on the surface.
2. Focus: (Principal focus) It is a point on the principal axis of the mirror, such that the rays incident on the mirror parallel to the principal axis after reflection, actually meet at this point (in case of a concave mirror) or appear to come from it (in case of a convex mirror)
3. Centre of Curvature: The centre of the spherical shell, of which the mirror forms a section, is called the centre of curvature of the mirror. It lies outside the surface. Every point on the mirror surface lies at same distance from it.
4. Aperture: The diameter of the circular rim of the mirror, is called the aperture of the mirror.
5. Principle Axis: The straight line passing through the pole P and the centre of curvature C of the mirror, is called principal axis of the mirror.
6. Normal: The normal at any point of the spherical mirror is the straight line obtained by joining that point with the centre of the mirror. 
Hope that satisfies your query.

Answered by  | 11th Oct, 2010, 08:39: PM

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