What is the unit of magnification of a microscope ?

Options

A. Centimetre
B. None
C. Metre
D. Dioptre

Answer

To determine the unit of magnification of a microscope, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Magnification**: Magnification (M) in the context of a microscope refers to how much larger an object appears when viewed through the microscope compared to its actual size. It is a measure of the increase in size of the image relative to the object.

2. **Formula for Magnification**: The magnification of a microscope can be expressed using the formula:
\[ M = \frac{V_O}{P_O} \times \frac{D}{F_E} \]
where:
- \( V_O \) = distance of the image from the objective lens
- \( P_O \) = distance of the object from the objective lens
- \( D \) = distance of distinct vision (the distance at which the eye can see an object clearly)
- \( F_E \) = focal length of the eyepiece

3. **Analyzing the Units**: In the formula for magnification, all the terms involved (distances) are measured in units of length (meters, centimeters, etc.). When calculating magnification, you are taking the ratio of distances:
\[ M = \frac{\text{length}}{\text{length}} \times \frac{\text{length}}{\text{length}} \]
This means that the units of length will cancel out.

4. **Conclusion on Units**: Since magnification is a ratio of two lengths, it is a dimensionless quantity. Therefore, magnification does not have a unit.

5. **Final Answer**: The unit of magnification of a microscope is **none**; it is a dimensionless quantity.