4D History - 4D Statistic

power 4dThe focal length of a lens with a power of +4D is 25 cm. Show More | Share Save. Class 12 PHYSICS GEOMETRICAL OPTICS. Topper's Solved these Questions. OPTICS BOOK -Power Toto 655 Hot & Cold Numbers. You probably noticed that some numbers just seem to appear in every other draw! These frequently drawn numbers are known as