# What is the wavelength of the sound waves?

## Homework Statement

a stationary sound wave has a series of nodes. The distance between the first and the sixth node is 30.0 cm. What is the wavelength of the sound waves?

## The Attempt at a Solution

well no idea about it
but in my attempt to solve it, i tried assuming 2L = $$\lambda$$
but there are 6 nodes so $$\lambda$$ = $$\frac{1}{3}$$L
by substituting the value of dist, i get $$\lambda$$ = 10cm
which is wrong. the ans is 12.0 cm
i wonder how to solve it

## Answers and Replies

Try drawing yourself a diagram of the problem (ie just draw a wave going through six nodes), you should be able to solve it a bit more easily once you can visualise it.

Your current working is neglecting the fact that there are two nodes at either end of this hypothetical wave. (kind of analogous to a similar problem you are probably familiar with - ie if a farmer had 100m of wire to build a fence and he could place the posts 2m apart, how many posts would he need?)

i think i know it
probably i should count the between one
so it should be $$\frac{2}{5}$$ L = $$\lambda$$
by computing it
i get 12.0 cm
yeah
thx all of you