A beam of light consisting of wavelengths 6000 `Å` and 4500 `Å` is used in a YDSE with D = 1 m and d = 1 mm. Find the least distance from the central maxima, where bright fringes due to the two wavelengths coincide.

Explanation

To solve the problem, we need to find the least distance from the central maxima where the bright fringes due to two wavelengths (6000 Å and 4500 Å) coincide in a Young's Double Slit Experiment (YDSE).

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Wavelengths:
- \( \lambda_1 = 6000 \, \text{Å} = 6000 \times 10^{-10} \, \text{m} \)
- \( \lambda_2 = 4500 \, \text{Å} = 4500 \times 10^{-10} \, \text{m} \)
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