The ratio of the size of the image to the size of the object is known as

Options

A. the focal plane
B. the transformation ratio
C. the efficiency
D. none of these

Answer

To solve the question "The ratio of the size of the image to the size of the object is known as," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Terms**:
- The size of the image refers to the height of the image (h_i).
- The size of the object refers to the height of the object (h_o).

2. **Identify the Ratio**:
- We need to find the ratio of the height of the image to the height of the object, which can be expressed mathematically as:
\[ \text{Magnification (m)} = \frac{h_i}{h_o} \]

3. **Define Magnification**:
- Magnification is a term used in optics to describe how much larger or smaller an image is compared to the object.
- If \( m > 1 \), the image is larger than the object.
- If \( m < 1 \), the image is smaller than the object.

4. **Evaluate the Options**:
- The question may provide multiple-choice answers. We need to evaluate each option:
- **Focal Plane**: This refers to the plane where light rays converge and is not related to the ratio of image to object size.
- **Transformation Ratio**: This is related to electrical transformers and is not applicable here.
- **Efficiency**: This term relates to the performance of machines and is not relevant to optics.
- **None of the Above**: Since none of the previous options correctly describe the ratio of image size to object size, this is the correct choice.

5. **Conclusion**:
- The ratio of the size of the image to the size of the object is known as **magnification**. Since this term is not listed among the options, the correct answer is **None of the Above**.

### Final Answer:
The ratio of the size of the image to the size of the object is known as **magnification**.