Mechanical Properties Of Fluids

Question

A resonance air column of length 40 cm resonates with tunning fork of frequency 450Hz. Ignoring end corrections , the velocity of sound in air will be

1020m/s

920m/s

820m/s

720m/s

Solution

720m/s

We know that the minimum length of the air column tube corresponds to the fundamental mode of vibrations. Hence by ignoring end corrections

Length of column =40cm=0.4m

Frequency of tuning fork = 450 Hz

Using the formula n= $\frac{ν}{4 l}$

or v= 450×4×0.4=720m/s