From a wave model perspective, the intensity of a sound (i.e. its "loudness") is dependent on the amount of energy that the sound wave carries. The energy of the wave is proportional to the...
It isn't - the two are distinct, and as such, each asserted independently in testimony; for example, "I, John Smith, being sound of mind and body, hereby bequeath my wordly goods to Jane Doe..."
The loudness of sound is related to the amplitude (or magnitude) of the vibration that is the sound. The frequency of the sound is not related to its loudness. A certain pitch can be loud or soft....