How can the loudness of a sound be increased in terms of wave properties?

• A. Increasing the amplitude
• B. Increasing the wavelength
• C. Increasing the frequency
• D. Increasing the speed

Answer: (A)

Loudness depends on how big the pressure swings are in the air, which is the amplitude of the sound wave. When you increase the amplitude, the pressure variations become larger, delivering more energy to the air each second. The energy (intensity) of a sound wave is proportional to the square of this amplitude, and our ears perceive this greater energy as a louder sound.

Raising wavelength would change the pitch (in a given medium, longer wavelength means lower frequency) but doesn’t inherently make the sound louder. Increasing frequency raises pitch rather than loudness, unless the amplitude is also increased. Increasing the speed of the wave is determined by the medium and doesn’t by itself boost loudness.