The concavo-convex lens has

Options

A. one convex, one concave
B. both convex
C. both concave
D. One plane, one convex

Explanation

To solve the question regarding the characteristics of a concavo-convex lens, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Lens Types**:
- A lens is a transparent optical device that refracts light. There are different types of lenses, primarily classified as convex and concave lenses.

2. **Defining Concavo-Convex Lens**:
- A concavo-convex lens, also known as a meniscus lens, is characterized by having one side that is concave (curved inward) and the other side that is convex (curved outward).

3. **Analyzing the Options**:
- The question provides four options:
1. One side convex and one concave
2. Both convex
3. Both concave
4. One plane and one convex

4. **Evaluating Each Option**:
- **Option 1**: One side convex and one concave - This is the correct description of a concavo-convex lens.
- **Option 2**: Both convex - This describes a biconvex lens, which is not correct.
- **Option 3**: Both concave - This describes a biconcave lens, which is also not correct.
- **Option 4**: One plane and one convex - This describes a plano-convex lens, which is not correct.

5. **Conclusion**:
- Based on the definitions and evaluations, the correct answer is that a concavo-convex lens has one side that is convex and one side that is concave.

### Final Answer:
The concavo-convex lens has **one side convex and one concave**.

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