Question

If the velocity of sound in air is 336 m/s. The maximum length of a closed pipe that would produce a just audible sound will be

• A. 3.2 cm
• B. 4.2 m
• C. 4.2 cm
• D. 3.2 m

Answer 1

The correct option is B

4.2 m

Minimum audible frequency = 20 Hz.

$\therefore \frac{v}{4l}=20\Rightarrow l=\frac{336}{4\times 20}=4.2m$