A sinusoidal progressive wave travels along the positive x-direction with amplitude A, angular frequency ω, wave number k and initial phase φ. Which expression can represent the displacement y of a particle of the medium at position x and time t?
Options

Question

A sinusoidal progressive wave travels along the positive x-direction with amplitude A, angular frequency ω, wave number k and initial phase φ. Which expression can represent the displacement y of a particle of the medium at position x and time t?

Options

G1 Physics · Accepted Answer

For a progressive wave travelling in the +x direction, a point of constant phase must move towards increasing x. Take kx−ωt+φ = constant. Differentiating, k dx/dt−ω = 0. Hence, dx/dt = ω/k > 0. Therefore a wave moving along +x may be written as y = A sin(kx−ωt+φ). Correct option: A.