If a lens has a power of -2 D, what type of lens is it?

If a lens has a power of -2 D, what type of lens is it?

Step 1: Understand what lens power means. Lens power is measured in diopters (D).
Step 2: Recognize that the sign of the power indicates the type of lens.
Step 3: Note that a positive power indicates a convex lens, which is thicker in the middle.
Step 4: Understand that a negative power indicates a concave lens, which is thinner in the middle.
Step 5: Since the given power is -2 D, it is negative.
Step 6: Conclude that a lens with a power of -2 D is a concave lens.

Lens Power – The power of a lens is the reciprocal of its focal length in meters. A negative power indicates a concave lens, while a positive power indicates a convex lens.