Two points are located at a distance of $10 \mathrm{~m}$ and $15 \mathrm{~m}$ from the source of oscillation…
- $\frac{\pi}{3}$
- $\frac{2 \pi}{3}$
- $\pi$
- $\frac{\pi}{6}$
Solution
$=\frac{2 \pi}{\lambda} \times \text { path difference }$
Path difference between two points,
$\Delta x=15-10=5 \mathrm{~m}$
Time period, $T=0.05 \mathrm{~s}$
$\Rightarrow$ frequency $v=\frac{1}{T}=\frac{1}{0.05}=20 \mathrm{~Hz}$
Velocity, $y=300 \mathrm{~m} / \mathrm{s}$
$\therefore$ Wavelength, $\lambda=\frac{v}{v}=\frac{300}{20}=15 \mathrm{~m}$
Hence, phase difference
$\begin{aligned}
\Delta \phi & =\frac{2 \pi}{\lambda} \times \Delta x \\
& =\frac{2 \pi}{15} \times 5=\frac{2 \pi}{3}
\end{aligned}$ :
Asked in: NEET 2008 (Screening)