power 4dDemension : 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.The 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 -