question_answer

A slab of glass of thickness 5 cm and refractive index 1.5 is held a few centimeter in front of a concave mirror of radius of curvature 40 cm. The faces of the slab being perpendicular to the principal axis of the mirror. How far (in cm) from the mirror must a small object be placed if its image coincides with the object? [consider all events].

Answer:

41.67