Question

Which of the following equations represents a simple harmonic progressive wave travelling along the negative X-direction?

विकल्प

• Y = a sin (kx − ωt)

• Y = a sin (kx + ωt)

• Y = a sin (ky − ωt)

• Y = a sin (ky + ωt)

Answer 1

Y = a sin (kx + ωt)

Explanation:

Direction (X vs. Y): The wave travels along the X-axis, so the equation must use the spatial variable x. 

Sign Convention:

•  A minus sign (kx − wt) indicates propagation in the positive direction.
• A plus sign (kx + wt) indicates propagation in the negative direction.