Question

Define 'bel' and
phon'. Describe a method for the determination of intensity of a source of sound.
Discuss the theory of forced vibration.​

Answer 1

Bel is the unit of measurement of sound intensity in terms of relative power.

Explanation:

• Bel is the unit of measurement of sound intensity in terms of relative power.
• It is denoted as log 10(p1 / p2).  
• "phon" is the unit of loudness and is equal to the number of decibels.
• If a source has large amplitude then it will produce sound f great intensity.
• Sound produced by a drum had large instesity.
• Vibration of sound is produced by compression and rearfaction as it travels in air.