JAMB Physics 2016 Paper

Concept:The beat frequency is the absolute difference between the frequencies of two sound sources.Explanation:When two tuning forks of slightly different frequencies are sounded together, periodic loudness variations occur.These variations are called beats.The number of beats heard per second equals the difference between the two frequencies.Here, the tuning fork frequencies are $258\text{ Hz}$ and $270\text{ Hz}$.So, beat frequency $= |270 - 258|$ Hz.Computing the difference gives $12$ Hz.Therefore, the beat frequency produced is $12$ Hz.Answer:$12$ Hz, which is option D.