Concave and convex lenses are placed touching each other. The ratio of magnitudes of their power is 2:3. The focal length of system is 30cm. The focal lengths of individual lenses are (A) -75 50 (B) -15.10 (C) 75 -50 (D) 25.-10

A convex lens is in contact with a concave lens. The magnitude of the ratio of their powers is (3)/(2) . Their equivalent focal length is 30 cm. What are their individual focal lengths?

A comvex lens and a concave lens are placed in contact. The ratio of magnitude of the power of the convex lens to that of the concave lens is 4:3. If the focal length of the convex lens is 12 cm, then the focal length of the combination will be

Two lenses are placed in contact with each other and the focal length of combination is 80 cm . If the focal length of one is 20 cm , then the power of the other will be

A convex lens if in contact with concave lens. The magnitude of the ratio of their focal length is (2)/(3) . Their equivalent focal length is 30 cm. What are their individual focal lengths?

A thin convex lens of focal length 10 cm is placed in contact with a concave lens of same material and of same focal length. The focal length of combination will be

Two convex lenses of equal focal lengths are kept in contact with each other. If the power of their combination is 20 D, find the focal length of each convex lens.

Two convex lenses of equal focal lengths are kept in contact with each other. If the power of their combination is 20 D, find the focal length of each convex lens.