is the principal axis positive for both concave and convex mirrors?

Asked by suryap2 | 23rd Sep, 2010, 08:40: PM

Expert Answer:

When a source of light is far from the mirror, and lies on the principal axis, the rays of light from it would be almost parallel to the principal axis.

The principal focus of a spherical mirror may be defined as a point on its principal axis where a beam of light parallel to the principal axis converges to or appears to diverge from, after reflection from the spherical mirror. _

Thus, the sign depends on the sign convention you are using.

Answered by  | 24th Sep, 2010, 01:53: PM

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