Question

Two stereo speakers are separated by a distance of 2.4 m. A person stands at a distance of 3.2 m as shown directly in front of one of the speakers. Find the frequencies in audible range for which the listener will hear a minimum sound intensity :
Speed of the sound in air is $320m{s}^{-1}$

• A. $160(2n+1)$
• B. $320(2n+1)$
• C. $200(2n+1)$
• D. $100(2n+1)$

Answer 1

The correct option is C $200(2n+1)$

$\sqrt{{3.2}^2+{2.4}^2}=4m$
path difference = $0.8m=(2n+1)\frac{\lambda }{2}$

$\lambda =\frac{1.6}{(2n+1)}usingf=\frac{v}{\lambda }=\frac{320}{1.6}(2n+1)$.
$=200(2n+1)Hz.$
$n=1,2,3,.....49$ are allowed