For which of the following colour, the magnifying power of a microscope will be maximum

Options

A. White colour
B. Red colour
C. Violet colour
D. Yellow colour

Answer

To determine which color provides the maximum magnifying power of a microscope, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Formula for Magnifying Power**:
The magnifying power (M) of a microscope is given by the formula:
\[ M = 1 + \frac{D}{f} \]
where \(D\) is the near point distance (the least distance of distinct vision) and \(f\) is the focal length of the lens.

2. **Relationship Between \(D\) and Wavelength**:
It is important to note that the distance \(D\) is inversely proportional to the wavelength (\(\lambda\)) of the light used:
\[ D \propto \frac{1}{\lambda} \]
This means that as the wavelength decreases, the distance \(D\) increases.

3. **Identify the Colors and Their Wavelengths**:
The visible spectrum of light can be represented by the acronym "VIBGYOR":
- Violet (shortest wavelength)
- Indigo
- Blue
- Green
- Yellow
- Orange
- Red (longest wavelength)

The order of colors from shortest to longest wavelength is:
\[ \text{Violet} < \text{Indigo} < \text{Blue} < \text{Green} < \text{Yellow} < \text{Orange} < \text{Red} \]

4. **Determine Which Color Maximizes Magnifying Power**:
Since \(D\) is inversely proportional to the wavelength, the color with the shortest wavelength (which is violet) will yield the largest value of \(D\). Thus, substituting into the magnifying power formula, we find that:
- When using violet light, \(D\) is maximized, leading to a higher magnifying power.

5. **Conclusion**:
Therefore, the color that provides the maximum magnifying power of a microscope is **violet**.

### Final Answer:
The magnifying power of a microscope will be maximum for the color **violet**.

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