A progressive wave travelling along the positive $x$-direction is represented by $y(x, t)=A$ sin $(\mathrm{kx}-\omega \mathrm{t}+\phi)$. Its snapshot at $\mathrm{t}=0$ is given in the figure: For this wave, the phase $\phi$ is :

JEE Main · 2019 · 12 Apr 2019 · Shift 1 · Waves & Sound

A progressive wave travelling along the positive

x

-direction is represented by

y (x, t) = A

sin

(kx - ω t + ϕ)

. Its snapshot at

t = 0

is given in the figure:

For this wave, the phase

ϕ

is :

Answer: (B)

t = 0

the wave profile is

y (x, 0) = A sin (k x + ϕ)

. The snapshot shows that at

x = 0

the displacement is already at its greatest positive value,

y = A

. That requires

sin ϕ = 1

, so the phase is

ϕ = \frac{π}{2}

JEE Main · 2019 · 12 Apr 2019 · Shift 1 · Single correct option