Question

the rays after refraction converge or diverge at a point on the principal axis. that point is known as _________​

Answer 1

Answer:

principal focus

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Answer 2

Answer:

principal focus of concave lens

Explanation:

Principal focus of concave lens: All the light rays after passing through the concave lens diverge and when produced backwards appear to meet at a point on the principal axis of the lens. This point is known as principal focus of a concave lens. Thus refracted rays appear to diverge from the focus.