Question

The displacement y of wave travelling in the x-direction is given by
$y={10}^{-4}\sin (600t-2x+\frac{\pi }{3})$ metres,
where $x$ is expressed in metres and $t$ in seconds. The speed of the wave-motion, in $m{s}^{-1}$ is

• A. $300$
• B. $600$
• C. $1200$
• D. $200$

Answer 1

Answer: (A)

$300$

$Velocity=Wavelength\times Frequency$

$Frequency\left(f\right)=\frac{\omega }{2\pi }=\frac{600}{2\pi }$

$Wavelength\left(\lambda \right)=\frac{2\pi }{k}=\frac{2\pi }{2}=\pi$

$Velocity=\pi \times \frac{600}{2\pi }=300m{s}^{-1}$