Question

The focal length of a concave mirror in air is f. if it is immersed in water [n=4/3], then the focal length will be

Answer 1

 The angle of reflection will always be same as the incident ray's angle; irrespective of the medium.

Only lens has effect on medium change because it works on refraction. And mirrors work with reflection.So , therefore focal length of concave mirror is same.

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