Concave lens and convex lens

Explanation

To differentiate between a concave lens and a convex lens, we can outline the key characteristics and differences step by step:

### Step-by-Step Solution:

1. **Definition and Structure**:
- **Concave Lens**: A concave lens is a lens that is thicker at the edges and thinner at the center. It is shaped like a cave, hence the name "concave."
- **Convex Lens**: A convex lens is thicker in the middle and thinner at the edges. It bulges outward, resembling a magnifying glass.

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