MCQ
Two waves are propagating along a taut string that coincides with the $x-$axis. The first wave has the wave function $y_1 = A cos [k(x - vt)]$ and the second has the wave function $y = A cos [k(x + vt) + \phi ]$.
- AFor constructive interference at $x = 0, \phi = \pi $.
- BFor constructive interference at $x = 0, \phi = 3\pi .$
- ✓For destructive interference at $x = 0, \phi = \pi$ .
- DFor destructive interference at $x = 0, \phi = 2\pi$ .

