Question

The phase difference between two points is $\pi /3$ . If the frequency of waves is $50 \, Hz$ , then, the distance between two points is (Given $v=330 \, m \, s^{- 1}$ )

• A. $2.2 \, m$
• B. $1.1 \, m$
• C. $0.6 \, m$
• D. $1.7 \, m$

Answer 1

Answer: (B)

From the relation,
$\Delta \phi=\frac{2 \pi }{\lambda }\times \Delta x$
$\Longrightarrow \Delta x=\frac{\lambda }{2 \pi }\times \Delta \phi \, \, \ldots \left(i\right)$
Also, $ \, \, \lambda =\frac{v}{n} \, \, \ldots \left(i i\right)$
Now, from Eqs.(i) and (ii), we get
$\Delta x=\frac{v}{2 \pi n}\times \Delta \phi$
$\Longrightarrow \, \, \, \Delta x=\frac{330}{2 \pi \times 50}\times \frac{\pi }{3}$
$or \, \Delta x=1.1 \, m$