Question

In Quincke's tube a detector detects minimum intensity. Now one of the tube is displaced by 5 cm. During displacement detector detects maximum intensity 10 times, then finally a minimum intensity (when displacement is complete). The wavelength of sound is:

• A. $\frac{10}{9}$ cm
• B. $1$cm
• C. $\frac{1}{2}$ cm
• D. $\frac{5}{9}$ cm

Answer 1

Answer: (B)

$1$cm

Since 10 maxima were observed in between the points separated by $5cm,$ the distance is equal to 10 half wavelengths.

Thus $5cm=10\times \frac{\lambda }{2}$

$⟹\lambda =1cm$