Doctor has prescribed a lens having power +1.5 D. What will be the focal length of the lens? What is the type of the lens and what must be the defect of vision?

Here, the power of a lens is given as +1.5 D

Meanwhile, we know the power of lens = 1/focal length = 1/f

So, P =1/f

That is +1.5 D = 1/f

Hence, f = 1/1.5 = 10/15 = 2/3 = + 0.67 m.

So the focal length = + 0.67m.

Here, the lens is a converging type of lens or convex lens and the defect of the eye is Hyperopia or farsightedness.