A biconvex thin lens is prepared from glass of refractive index `mu_(2)=(3)/(2)`. The two conducting surfaces have equal radii of 20 cm each. One of the the surface is silvered from outside to make it reflecting. It is placed in a medium of refractive index `mu_(1)=(5)/(3)`. It acts as a

Options

A. converging mirror
B. diverging mirror
C. concave mirror of focal length 12.5 cm
D. convex mirror of focal length 12.5 cm

Answer

A, C