State the principle on which a megaphone works. Explain it's working.

Hint : A megaphone could be a funnel shaped instrument that is employed to amplify sound. It’s just like that of a loudspeaker. The funnel-like shape of the megaphone helps during amplifying the sound and sends the sound within a particular direction.

Complete step-by-step solution:
A megaphone may be a funnel-shaped instrument that is employed to amplify sound. You will have seen in rallies or some public speeches, people employing a megaphone to create their voice sound louder. One can think about a megaphone as a loudspeaker.
We know that sound could be a wave. Waves have the property of reflecting at the surface or when there’s a change in medium (similar to light). Therefore, sound waves also reflect after they hit an obstacle and this is the reason why we will hear our own voice. The sounds waves from our mouths hit the encompassing obstacles and acquire reflected. These types of reflected waves then enter our ears.
A megaphone works on the principle of multiple reflections of sound waves. We all know that a megaphone is within the shape of a funnel. As a result, when sound is produced within a megaphone, the waves are reflected many times and travel within a path leading to the opening of the funnel. Because of this, the amplitude of the sound increases and they travel within a specific direction.

Note: Actually, a megaphone is predicated on the principle of superposition of waves too. When two or more waves superimpose, a new wave is made. The amplitude of the resultant wave could also be greater than the initial waves. This is often how the sound is amplified with a megaphone.