Question

In a resonance tube experiment when the tube is filled with water up to height of $17.0\, cm$ from bottom, it resonates with a given tuning fork. When the water level is raised the next resonance with the same tuning fork occurs at a height of $24.5 \,cm$. If the velocity of sound in air is $330\, m / s$, the tuning fork frequency is:

• A. $1100\, Hz$
• B. $3300\, Hz$
• C. $2200 \,Hz$
• D. $550\, Hz$

Answer 1

Answer: (C)

$\Rightarrow \lambda=2\left(l_{2}-l_{1}\right) $
$\Rightarrow 2 \times(24.5-17)$
$\Rightarrow 2 \times 7.5=15\, cm$
& $v = f \lambda $
$\Rightarrow 330=\lambda \times 15 \times 10^{-2}$
$\lambda=\frac{330}{15} \times 100$
$ \Rightarrow \frac{1100 \times 100}{5}$
$\Rightarrow 2200 \,Hz$