Question

The velocity of waves in a string fixed at both ends is 2 m/s. The string forms standing waves with nodes 5.0 cm apart. The frequency of vibration of the string in Hz is

• A. $40$
• B. $30$
• C. $20$
• D. $10$

Answer 1

Answer: (C)

$20$

Here the distance between the two nodes is half of the wavelength

$\frac{\lambda }{2}=5.0cm\Rightarrow \lambda =10cm$

Hence $n=\frac{v}{\lambda }=\frac{200}{10}=20Hz$