Question

The equations of waves emitted $S_1,S_2,S_3$ and $S_4$ are respectively $y_1=20\sin \left(100\pi t\right),y_2=20\sin \left(200\pi t\right),y_3=20\cos \left(100\pi t\right)$ and $y_4=20\cos \left(100\pi t\right)$. The phenomenon of interference will be produced by

• A. $y_1$ and $y_2$
• B. $y_2$ and $y_3$
• C. $y_1$ and $y_3$
• D. Interference will not possible

Answer 1

The correct option is A $y_1$ and $y_2$

To set up a stable and clear interference pattern, two conditions must be met:

The sources of the waves must be coherent, which means they emit identical waves with a constant phase difference.
And the waves should be monochromatic - they should be of a single wavelength.

Since the frequency of $y_1$ and $y_2$ is same, they form interference pattern.