Question

In Young's experiment, the intensity ratio of the maxima and minima in an interference pattern produced by two coherent sources is \(36:1\). The ratio of the amplitudes of the two individual sources will be

• A. \(4:7\)
• B. \(5:7\)
• C. \(7:5\)
• D. \(7:4\)

Hint:

In a medium the wavelength is divided by the refractive index.

Answer 1

The Correct Option is C

Step 1: Wavelength in water:
\(\lambda' = \frac{\lambda}{n} = \frac{6300\text{ \AA}}{1.33}\).

Step 2: Fringe width:
\[ \beta = \frac{\lambda'D}{d} = \frac{6300\times10^{-10}}{1.33}\times\frac{1.33}{1\times10^{-3}} = 6.3\times10^{-4}\text{ m} \]
The 1.33 in the wavelength and in the distance cancel exactly.

Final Answer:
The fringe width is \(6.3\times10^{-4}\) m, option (B). \[ \boxed{6.3\times10^{-4}\text{ m}} \]