Question

In a resonating air column, _ _ _ _ _ _ waves are formed.

Answer 1

Hint: A standing wave is formed when two waves of same amplitude and same frequency, moving with same speed but opposite in direction interfere. A resonance air column is a tube (either both ends closed or only end closed), in which standing waves can be produced.

Complete answer:
In a resonating air column, longitudinal standing waves are formed.A standing wave is formed when two waves of same amplitude and same frequency, moving with same speed but opposite in direction interfere. A standing wave does not propagate in any direction and it oscillates at one place. Therefore, it is also called a stationary wave.

When both the interfering waves are longitudinal waves, a longitudinal wave is formed.A resonance air column is a tube (either both ends closed or only end closed), in which standing waves can be produced. It is also called an organ pipe. These are used in musical instruments to produce musical tones.The equation of a standing wave is given as,
$s=2{{s}_{0}}\sin \left( kx+\phi \right)\cos \left( \omega t+\phi \right)$ …. (i),
where s is the displacement of a particle at position x at time t, ${{s}_{0}}$ is a constant, k is wave number, $\omega$ is the angular frequency of the wave and $\phi$ is the phase angle.
We can see that equation (i) does not represent the equation of an ordinary wave, i.e. $y=f(kx\pm \omega t)$.
Therefore, the wave is not travelling and the amplitude of a particle at x is equal to$2{{s}_{0}}\sin \left( kx+\phi \right)$.

Note: We can simply say that a standing wave is a wave that just oscillates and does not travel.A standing wave consists of nodes and antinodes. Nodes are the points where the amplitude of the particles is zero. Antinodes are the points where the amplitude of the articles is maximum.These nodes and antinodes are consecutive.