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The principal focus of a spherical mirror, for small apertures, lies:
AExactly at the pole of the mirror
BMidway between pole and centre of curvature
CAt the centre of curvature of the mirror
DTwice as far as the centre of curvature
Answer & Solution
Correct answer: B. Midway between pole and centre of curvature
For small-aperture mirrors, R = 2f, so the focus F sits exactly midway between the pole P and the centre of curvature C.
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