Question

Sound of wavelength l passes through a Quincke's tube, which is adjusted to give a maximum intensity I₀. Through what distance should the sliding tube be moved to give an intensity I_­0/2 ?

• A. l/2
• B. l/3
• C. l/4
• D. l/8

Answer 1

Answer: (D)

l/8

Answer 2

4 I = I₀

for Intensity $\frac{I_{0}}{2}$ i.e 2I

Df = $\frac{\pi}{2}$ = $\frac{2\pi}{\lambda}$ Dx

Dx = $\frac{\lambda}{4}$ = 2x \ x = $\frac{\lambda}{8}$