In Young's double slit experiment, the phase difference between the light waves reaching third bright fringe from the central fringe will be `(lambda=6000Å)`

Options

A. (a) Zero
B. (b) `2pi`
C. (c) `4pi`
D. (d) `6pi`

Explanation

To find the phase difference between the light waves reaching the third bright fringe from the central fringe in Young's double slit experiment, we can follow these steps:

### Step 1: Understand the relationship between fringe order and phase difference
In Young's double slit experiment, the phase difference (\(\Delta \phi\)) between the light waves reaching a given fringe can be expressed as:
\[ \Delta \phi = 2n\pi \]
where \(n\) is the order of the fringe (0 for the central fringe, 1 for the first bright fringe, 2 for the second bright fringe, and so on).

### Step 2: Identify the order of the fringe
For the third bright fringe, the order \(n\) is 3.

### Step 3: Substitute the value of \(n\) into the phase difference formula
Now, substituting \(n = 3\) into the formula:
\[ \Delta \phi = 2 \times 3 \times \pi = 6\pi \]

### Step 4: Conclusion
Thus, the phase difference between the light waves reaching the third bright fringe from the central fringe is:
\[ \Delta \phi = 6\pi \]

### Final Answer
The phase difference is \(6\pi\).

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