<em>A megaphone used by a cheerleader can allow people on the opposite side of a field to hear her better because;</em>
D. Solid objects can change the direction of sound waves; megaphones allow users to determine the general direction of the sound.
<u>Determination of the general direction of the sound lessens its dispersion and thus, it reaches the observers at a higher intensity, hence it being louder.</u>
Explanation: Experience has taught us that the tone can help determine the direction of the sound waves. People riding a motorbike wearing a helmet, for example, often find it difficult to hear where an ambulance is coming from, as the helmet reduces the outer ear's ability to determine the tone of the sound.
When a person hears sounds of limited wavelengths, the head functions as a screen. If the sound comes from a direction to the right of the face, the head will prevent the sound waves from reaching the left ear. Deep base sounds, on the other hand, have a larger wavelength, and the head will not prevent the sound waves from reaching both ears.
