Question

Two waves of wavelength $1.00 \, m$ and $1.01 \, m$ produces $10 \, beats$ in $3 \, s$ . What is the velocity of the wave?

• A. $150 \, m \, s^{- 1}$
• B. $115.2 \, m \, s^{- 1}$
• C. $336.6 \, m \, s^{- 1}$
• D. $200 \, m \, s^{- 1}$

Answer 1

Answer: (C)

$\nu_{1}=\frac{v}{\lambda _{1}}=\frac{v}{1.00} \, and \, \nu_{2}=\frac{v}{\lambda _{2}}=\frac{v}{1.01}$
$\therefore \Delta \nu=\nu_{1}-\nu_{2}=v\left[\frac{1}{1.00} - \frac{1}{1.01}\right]=\frac{10}{3}$
$or \, \, v=\frac{10 \times 1 \times 1.01}{0.01 \times 3}$
$\therefore v=336.6 \, ms^{- 1}$