The plano-convex lens has

Options

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

Explanation

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

### Step-by-Step Solution:

1. **Understand the Definition of a Plano-Convex Lens**:
- A plano-convex lens is a type of lens that has one flat (plane) surface and one outwardly curved (convex) surface.

2. **Analyze the Given Options**:
- The options provided are:
a) Both surfaces convex
b) One plane and one convex surface
c) One convex and one concave surface
d) Both concave surfaces

3. **Evaluate Each Option**:
- **Option a**: Both surfaces convex - This is incorrect because a plano-convex lens has one flat surface.
- **Option b**: One plane and one convex surface - This is correct as it describes the structure of a plano-convex lens accurately.
- **Option c**: One convex and one concave surface - This is incorrect because a plano-convex lens does not have a concave surface.
- **Option d**: Both concave surfaces - This is incorrect as a plano-convex lens cannot have two concave surfaces.

4. **Conclusion**:
- The correct answer is **Option b**: One plane and one convex surface.

### Final Answer:
The plano-convex lens has **one plane and one convex surface**.

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