power 4d6. A convex lens of power +6 D is placed in contact with a concave lens of power –4D. What will be the nature and focal length of this combination ? (a) convex, 100 cm (b) convex, 50 cmDemension : 23.5 x 17.5 x 5.2 cm. Output Power in 4 ohm : 1 x 1500 W. Output Power in 2 ohm : 1 x 3000 W. Output Power in 1 ohm : 1 x 4500 W.