The power of a lens is +4D. What is the nature of lens

power 4dA convex lens of power 4D is kept in contact with a concave lens of power 3D, the effective power of combination will be . View Solution; Knowledge Check. A convex lens of focal length 40 cmIn collaboration with HAPPY POWER. Only 300PCS Produced. Features: Full Size 36x18; Our Champion-Grade Speed + Control Surface; Soft Rubber Anti