Question

Two in-phase loudspeakers, which emit sound in all directions, are sitting side by side. One of them is moved sideways by 4.0 mm, then forward by 2.0 mm. Afterward, constructive interference is observed 1414, 1212, and 3434 the distance between the speakers along the line that joins them, and at no other positions along this line. Part A What is the maximum possible wavelength of the sound waves ?

Answer 1

Answer:

4.4721m

Explanation:

#Use Pythagorean theorem to find the distance between the two speakers:

$a^+b^2=c^2\\4^2+2^2=d^2\\\sqrt{20}\ mm=d$

There are antinodes 1/4,1/2 and 3/4 of the distance between speakers.

The greatest antinode is 3/4-1/4=1/2

#Distance between consecutive antinodes is:

$0.5\times \sqrt{20}=\lambda/2\\\\\lambda=4.4721m$

Hence, the maximum possible wavelength of the sound waves is 4.4721m