Help with Question needed!!!

[lakvinu]

Hello,

Can someone please help me with this question?

Thanks

[Theodric_Ironfist]

At time t=0, both waves have amplitude 0, so the resultant wave has amplitude 0. This rules out B.

At the next instant, both waves have the same amplitude at point Z, and both are positive, so the resultant wave has a positive amplitude, double that of X and Y. Thus option A.

In fact, at any time during this scenario both X and Y have equal amplitudes at Z due to symmetry, and so the resultant wave will always just have double the amplitude. Point Z is basically an antinode on a standing wave pattern.

[lakvinu]

At time t=0, both waves have amplitude 0, so the resultant wave has amplitude 0. This rules out B.

At the next instant, both waves have the same amplitude at point Z, and both are positive, so the resultant wave has a positive amplitude, double that of X and Y. Thus option A.

In fact, at any time during this scenario both X and Y have equal amplitudes at Z due to symmetry, and so the resultant wave will always just have double the amplitude. Point Z is basically an antinode on a standing wave pattern.

Hello,

Yes I thought the answer was A as well but the solutions was C. I attached the solution.

[Theodric_Ironfist]

Answer is definitely A, if you take wave X to be the one that looks like a positive sine wave, which is definitely what it looks like. NEAP has been wrong before...