In double slits experiment, for light of which colour the fringe width will be minimum

Options

A. violet
B. red
C. green
D. yellow

Explanation

To solve the problem of determining which color of light results in the minimum fringe width in a double slit experiment, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Fringe Width**:
The fringe width (β) in a double slit experiment is defined as the distance between two consecutive bright or dark fringes on the screen.

2. **Identify the Formula for Fringe Width**:
The formula for fringe width is given by:
\[ \beta = \frac{d \lambda}{D} \]
where:
- \( \beta \) = fringe width
- \( d \) = distance between the slits
- \( D \) = distance from the slits to the screen
- \( \lambda \) = wavelength of the light used

3. **Analyze the Relationship**:
From the formula, we can see that fringe width (β) is directly proportional to the wavelength (λ). This means that as the wavelength increases, the fringe width also increases.

4. **Determine the Wavelengths of Colors**:
The visible spectrum consists of different colors, each with a specific wavelength:
- Violet: ~380 nm (nanometers)
- Blue: ~450 nm
- Green: ~495 nm
- Yellow: ~570 nm
- Orange: ~590 nm
- Red: ~620 nm

5. **Identify the Color with Minimum Wavelength**:
Among the colors listed, violet has the smallest wavelength (approximately 380 nm).

6. **Conclude the Result**:
Since the fringe width is directly proportional to the wavelength, the color of light that will produce the minimum fringe width is violet.

### Final Answer:
The fringe width will be minimum for violet light.

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