Physics (AS & A Level) · May / June 2026 · Paper 14 · Question 31

The basic principle of note production in a horn is to set up a stationary wave in an air column. [diagram of horn with mouthpiece and bell] For any note produced by the horn, a node is formed at the mouthpiece, and an antinode is formed at the bell. The frequency of the lowest note is 75 Hz. What are the frequencies of the next two higher notes for this air column?

1. Afirst higher note: 113 Hz, second higher note: 150 Hz
2. Bfirst higher note: 150 Hz, second higher note: 225 Hz
3. Cfirst higher note: 150 Hz, second higher note: 300 Hz
4. Dfirst higher note: 225 Hz, second higher note: 375 Hz

As printed in the paper