The radius of curvature of a thin plano-convex lens is 10 cm (of curved surface) and the refractive index is 1.5. If the plane surface is silvered, then it behaves like a concave mirror of focal length

(a) 10 cm

(b) 15 cm

(c) 20 cm

(d) 5 cm

(a)

The silvered plano convex lens behaves as a concave mirror; whose focal length is given by

        If plane surface is silvered

 
1/F=2/f_1 +1/f_m

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ankit singh manit bhopal 3 year student forum answer expert @ askiitians