Question

the middle of the lens is called the

convex lens

optical center

focal length

focal point

Explanation:

To solve this, we analyze each option:

• "Convex Lens" is a type of lens, not the middle part.
• "Optical Center" is defined as the middle point of a lens, matching the question.
• "Focal Length" is the distance from the lens to the focal point, not the middle.
• "Focal Point" is where light converges, not the middle of the lens.

Answer:

B. Optical Center