power 4dA convex lens of power + 6D is placed in contact with a concave lens of power – 4D. What is the nature and focal length of the combination. see full answer. Start JEE NEET FoundationDapatkan keputusan 4D & Jackpot yang paling cepat di Malaysia secara langsung dari Magnum 4D (m4d), Sports Toto (t4d), Damacai 1+3D (Kuda). Dato4D - 4D Predict King (4D88).