Question

A set of open-ended pipes with waves vibrating inside them is shown as above figure.
Identify the pipe which contains the longest wavelength of sound?

• A. $A$
• B. $B$
• C. $C$
• D. $D$
• E. $E$

Answer 1

Answer: (B)

$B$

Let L be the length of organ pipe ,

for fig. A,

$L=2\lambda /2=\lambda$

$\lambda =L$

for fig. B,

$L=\lambda /2$

$\lambda =2L$

for fig. C,

$L=2\lambda /3$

$\lambda =3L/2$

for fig. D,

$L=5\lambda /2$

$\lambda =2L/5$

for fig. E,

$L=4\lambda$

$\lambda =L/4$

It is clear that fig B has maximum wavelength.