An organ pipe, open from both ends produces 5 beats per second when vibrated with a source of frequency 200 Hz. The second harmonic of the same pipes produces 10 beats per second with a source of frequency 420 Hz. The frequency of source is
Initially number of beats per second = 5
Frequency of pipe = 200 5 = 195 Hz or 205 Hz ...(i)
Frequency of second harmonics of the pipe = 2n and number of beats in this case = 10
2n = 420 10 410 Hz or 430 Hz
n = 205 Hz or 215 Hz ... (ii)
From equation (i) and (ii) it is clear that n = 205 Hz