Question

The disc of a siren containing $60$ holes rotates at a constant speed of $360\, rpm$. The emitted sound is in unison with a tuning fork of frequency :

• A. 10 Hz
• B. 360 Hz
• C. 216 Hz
• D. 60 Hz

Answer 1

Answer: (B)

360 Hz

Answer 2

Number of holes in the disk determines the number of waves produced on each rotation $= 60$
The total number of waves per second determines the frequency of the sound.
So frequency $=60 \times \frac{360}{60}=360 \,Hz$