Which of the following characteristics primarily determine the loudness or softness of sound?

Option 1 -> Amplitude is the maximum displacement of particles in a sound wave; greater amplitude means more energy and louder sound.

Option 2 -> Wavelength is the distance between successive wave crests; it relates to frequency and speed, not loudness.

Option 3 -> Frequency determines the pitch (high or low) of sound, not its loudness or softness.

Option 4 -> Time taken is not a characteristic that determines the loudness of sound.

Hence, Option 1: Amplitude -> The amplitude of a sound wave directly correlates with the energy carried by the wave. Higher amplitude means particles vibrate with greater displacement, producing louder sounds, while lower amplitude results in softer sounds. -> correct