Answer:
100 cm
Explanation:
It is given that there are two loudspeakers that produces [tex]$\text{sound waves }$[/tex] along x-axis.
The maximum intensity of the sound is [tex]$\text{when the speakers are}$[/tex] at a distance of = 15 cm apart.
The sound intensity becomes zero when the separation between the speakers are increased and becomes 65 cm.
Therefore, the sound waves are in the phase, [tex]$\Delta x_1=15 \ cm$[/tex]
The sound waves are out of phase when [tex]$\Delta x_2=65 \ cm$[/tex]
Therefore,
[tex]$\Delta x_2 - \Delta x_1 = \frac{\lambda}{2}$[/tex]
[tex]$\lambda= 2(\Delta x_2 - \Delta x_1)$[/tex]
= 2 (65 - 15)
= 2 x 50
= 100 cm
Hence the wavelength of the sound is 100 cm.