The fringe width in Young's double slit experiment can be increased by decreasing

Options

A. separationk between two slits.
B. width of the slit.
C. wavelength of light
D. distance between slit and the screen.

Explanation

To solve the question regarding how to increase the fringe width in Young's Double Slit Experiment (YDSE) by decreasing a certain parameter, we can follow these steps:

### Step 1: Understand the Concept of Fringe Width
Fringe width (β) in YDSE is defined as the distance between two consecutive bright or dark fringes in the interference pattern. It is an important parameter that determines the spacing of the interference pattern on the screen.

### Step 2: Identify the Formula for Fringe Width
The formula for fringe width (β) is given by:
\[ \beta = \frac{n \lambda D}{d} \]
where:
- \( \beta \) = fringe width
- \( n \) = order of the fringe (usually taken as 1 for the first order)
- \( \lambda \) = wavelength of the light used
- \( D \) = distance from the slits to the screen
- \( d \) = distance between the two slits

### Step 3: Analyze the Parameters
From the formula, we can see that:
- \( \beta \) is directly proportional to \( \lambda \) and \( D \).
- \( \beta \) is inversely proportional to \( d \) (the distance between the slits).

### Step 4: Determine Which Parameter to Decrease
To increase the fringe width (β), we need to decrease the parameter that is inversely proportional to β. Since \( \beta \) is inversely proportional to \( d \), decreasing the distance between the slits (d) will lead to an increase in fringe width.

### Step 5: Conclusion
Thus, the fringe width in Young's Double Slit Experiment can be increased by decreasing the distance between the slits (d).

### Final Answer
The correct answer is: **Decreasing the distance between the slits (d)**.

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