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

Answer 2

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

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