Question
If the focal length of a spherical mirror is 16 cm, what is its radius of curvature?
This question was previously asked in
RRB JE 2018 CBT 1 Question Paper English (30-May-2019) (Shift 3)
The correct answer is
32 cm
32 cm is correct.
For a spherical mirror the focus lies midway between the pole and the centre of curvature, so the radius of curvature is twice the focal length: \(R = 2f\).
\(R = 2\times16 = 32\) cm.
This relation holds for both concave and convex mirrors of small aperture, so the radius of curvature is 32 cm.
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