Power (P) of a lens is given by reciprocal of focal length (f) of

power 4dThe power to move, walk and travel in four dimensions. Sub-power of Unrestricted Movement and 4th-Dimensional Access. Technique of Space-Time Manipulation and Dimension Manipulation.6. 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 cm