Two pipes of equal length are each open at one end. Each has a fundamental frequency of 715 Hz at 300 K. In one pipe the air temperature is increased to 313 K. If the two pipes are sounded together, what beat frequency results?

Answer 1

v =331sqrt(T/273)
v1=331sqrt(300/273) =347 m/s
v2=331sqrt(313/273) =354 m/s
Fundamental frequency λ=4L
f=v/ λ =>
f1/f2 =v2/v1 =>
f2=f1(v2/v1)=715(354/347)=729 Hz
f(beat) =f2-f1= 729-715 =14 Hz