Question

A travelling harmonic wave is represented by the equation $y (x, t) = 10^{-3} sin (50 t + 2x)$, where $x$ and $y$ are in meter and $t$ is in seconds. Which of the following is a correct statement about the wave?
The wave is propagating along the

• A. negative x-axis with speed $25\,ms^{-1}$
• B. The wave is propagating along the positive x-axis with speed $25\,ms^{-1}$
• C. The wave is propagating along the positive x-axis with speed $100\, ms^{-1}$
• D. The wave is propagating along the negative x-axis with speed $100\, ms^{-1}$

Answer 1

Answer: (A)

$y = a \; \sin(\omega t + kx)$
$\Rightarrow $ wave is moving along $-ve$ x-axis with speed
$v = \frac{\omega}{K} \Rightarrow v = \frac{50}{2} =25m/\sec$