Question

An open-ended tube is 7.8 m long. What is the wavelength of a third harmonic standing wave?

Answer 1

`5.2m`

Explanation:

For an open ended tube,at both the ends antinodes are present,so for `1`st harmonic it's length `l` is equals to distance between two antinodes i.e `lambda/2` where, `lambda` is the wavelength.

So,for `3` rd harmonic `l=(3lambda)/2`

Or, `lambda =(2l)/3`

Given, `l=7.8m`

So,`lambda =(2×7.8)/3=5.2m`