Question

In a resonance - column experiment to measure the velocity of sound, the first resonance is obtained at a length $l_1$ and the second resonance at a length $l_2$. Which of the following is (are) correct?

• A. $l_2>3l_1$
• B. $l_2=3l_1$
• C. $l_2<3l_1$
• D. May be any of the above, depending on the frequency of the tuning fork used

Answer 1

The correct option is C

$l_2<3l_1$

$\lambda \to$ wavelength

$\delta \to$ end correction

$l_1=\frac{\lambda }{4}+\delta ;l_2=\frac{3\lambda }{4}+\delta$

or, $l_2=3(l_1-\delta )+\delta =3l_1-2\delta$