Question 399: Waves

Question

Two consecutive harmonics of an air column in a pipe closed at one end are of frequencies 150 Hz and 250 Hz. The fundamental frequency of an air column is

Accepted Answer

In a pipe closed at one end only odd harmonics of the fundamental are produced. If $$\mathrm{f}$$ is the fundamental frequency then the harmonics produced are $$3 \mathrm{f}, 5 \mathrm{f}, 7 \mathrm{f}, \ldots \ldots$$ The difference between the successive overtones is $$2 \mathrm{f}$$.
$$\begin{aligned}
& 	herefore 250 \mathrm{~Hz}-150 \mathrm{~Hz}=2 \mathrm{f} \
& 	herefore 100 \mathrm{~Hz}=2 \mathrm{f} \
& 	herefore \quad \mathrm{f}=50 \mathrm{~Hz}
\end{aligned}$$

Answer

25 Hz

Answer

75 Hz

Answer

100 Hz

Answer

50 Hz

Waves

Two consecutive harmonics of an air column in a pipe closed at one end are of frequencies 150 Hz and 250 Hz. The fundamental frequency of an air column is

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