Question

An interference is observed due to two coherent sources ‘A’ and ‘B’ having phase constant zero separated by a distance $4\lambda$ along the y-axis where $\lambda$ is the wavelength of the source. A detector D is moved on the positive x-axis. The number of points on the x-axis excluding the points $x=0$ and $x=\infty$ at which maxima will be observed is

• A. 3
• B. 4
• C. 5
• D. infinite

Answer 1

The correct option is A

3

At $x=0;\Delta x=4\lambda$

And at $x=\infty ,\Delta x=0$ except then, there are 3 maxima

Where $\Delta x=\lambda ,2\lambda$ and $3\lambda$ exist.