Question

In a standing wave pattern in a vibrating air column, nodes are formed at a distance of 4.0 cm. If the speed of sound in air is 328 m/s, what is the frequency of the source?

Answer 1

The distance between two consecutive nodes is equal to half of the wavelength of the vibration. This distance given here = 4.0 cm =0.04 m. 

Hence /2 = 0.04 m 

→ = 2*0.04 m =0.08 m 

Since the speed of sound in air, V = 328 m/s, so the frequency of the source, ν = V/ 

→ν = 328/0.08 Hz =32800/8 Hz  

→ν = 4100 Hz = 4.10 kHz.