Question

Two speakers on a horizontal axis both emit `440` Hz sound waves. The two speakers are `pi` radians out of phase. If there is to be a maximum constructive interference what is the minimum separation distance between the two speakers?

Answer 1

0.39 meters

Explanation:

Because the two speakers are off by `pi` radians, they are off by half a cycle. To have maximum constructive interference, they must line up exactly, meaning one of them must be shifted over half a wavelength.

The equation `v=lambda*f` represents the relationship between frequency and wavelength. The speed of sound in air is approximately 343 m/s, so we can plug that into the equation to solve for `lambda`, the wavelength.

`343=440lambda`
`0.78=lambda`

Finally, we must divide the value of the wavelength by two because we want to shift them over half a cycle.

`0.78/2=0.39` meters, which is your final answer.