Which of the following characteristics primarily determine the loudness or softness of sound?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Amplitude
The amplitude of a sound wave is the largest disturbance of the medium from its rest position. A larger amplitude carries more energy, so the sound is louder; a smaller amplitude gives a softer sound. A drum struck hard vibrates with a larger amplitude and sounds louder.
Why the other options are incorrect
Option (2) Wavelength — Incorrect. The distance between two consecutive compressions; in a given medium it is tied to the frequency, so it sets the pitch, not the loudness.
Option (3) Frequency — Incorrect. The number of vibrations per second; it decides the pitch (shrill or deep), not how loud the sound is.
Option (4) Time taken — Incorrect. The time for one vibration is the time period, the reciprocal of frequency, so it too relates to pitch.