A String That Is 0 $0.88 \mathrm {~m}$ Long and Open at Both Ends into Its Second Overtone

Multiple Choice

A string that is 0.26 m long is vibrating in its n = 6 harmonic. The sound from tthis string excites a pipe that is $0.88 \mathrm {~m}$ long and open at both ends into its second overtone resonance. What is the common resonant frequency of the string and the pipe? The speed of sound in air is 345 m/s.

A) 590 Hz
B) 390 Hz
C) 490 Hz
D) 690 Hz
E) 760 Hz