In a Young's double-slit experiment , the slits are separated by `0.28` mm and screen is placed `1.4` m away . The distance between the central bright fringe and the fourth bright fringe is measured to be `1.2` cm . Determine the wavelength of light used in the experiment .

Explanation

To solve the problem, we will use the formula for the position of bright fringes in a Young's double-slit experiment. The formula is given by:

\[ y_n = \frac{n \cdot \lambda \cdot D}{d} \]

Where:
- \( y_n \) is the distance from the central maximum to the nth bright fringe,
- \( n \) is the order of the fringe (in this case, \( n = 4 \)),
- \( \lambda \) is the wavelength of light,
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