question_answer 41)

  The radius of curvature of the curved surface of a plano-convex lens is 20 cm. If the refractive index of the material of the lens be 1-5, it will (a) act as a convex lens only for the objects that lie on its curved side (b) act as a concave lens for the objects that lie on its curved side (c) act as a convex lens irrespective of the side on which the object lies (d) act as a concave lens irrespective of side on which the object lies

Answer:

  (c)  Here,  =1-5 If object lies on plane side;  cm f= + 40 cm. The lens behaves as convex. If object lies on its curved side, cm. The lens behaves as convex.  Choice (c) is correct