Question

Two points are located at a distance of 10 m and 15 m from the source of oscillation. The period of oscillation is 0.05 sec and the velocity of the wave is 300 m/sec. What is the phase difference between the oscillations of two points?

• A. $\frac{\pi}{6}$
• B. $\frac{\pi}{3}$
• C. $\frac{2 \pi}{3}$
• D. $\pi$

Answer 1

Answer: (C)

We know that,
Path difference $=\frac{2 \pi}{\lambda} \times$ path difference
Path difference between two points,
$
\Delta x =15-10=5 m
$
Time period, $T =0.5 s$
$
\Rightarrow \text { frequency } v =\frac{1}{ T }=\frac{1}{0.05}=20 Hz
$
Velocity $v =300 m / s$
$\therefore$ Wavelenght $\lambda=\frac{ v }{ n }=\frac{300}{20}=15 m$
Hence, phase difference
$
\Delta \phi=\frac{2 \pi}{\lambda} \times x =\frac{2 \pi}{15} \times 5=\frac{2 \pi}{3}
$