power 4d6. 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 cmPower Workout 4D brings Fitness Information and Tips for people looking Easy Exercises and Workouts to Get in Shape and Lose Weht at Home without going to gym.