12. Define pole of a spherical mirror.
13. Define principal axis of the spherical mirror
14. Define the principal focus of a convex mirror.
15. Define the principal focus of a concave mirror.
16. Define focal length of a spherical mirror.
Answers
12. Define pole of a spherical mirror.
Ans:
The point where the principal axis pierces the mirror is called the pole of the mirror.
13. Define principal axis of the spherical mirror.
Ans:
a line passing through the center of the surface of a lens or spherical mirror and through the centers of curvature of all segments of the lens or mirror.
14. Define the principal focus of a convex mirror.
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The point at which the ray or beam of light which are travelling "parallel to the principal axis" either actually in real meets or appears virtually to meet, after the reflection, is called the principal focus. Principal focus of convex mirror is the point where the ray of light after reflection appears to meet.
15. Define the principal focus of a concave mirror.
Ans:
Light rays that are parallel to the principal axis of a concave mirror converge at a specific point on its principal axis after reflecting from the mirror. This point is known as the principal focus of the concave mirror.
16. Define focal length of a spherical mirror.
Ans:
the pole and the principal focus of the mirror, is called the focal length of the mirror. In diagram, PF is the focal length of the mirror. It is represented by the symbol f. For mirrors of small aperture, f=R/2.