Which of the following is a typical example of Impact/Impulse Noise?

• A. A loud hum from a transformer
• B. Riveting, weapon fire, explosives
• C. A fan running
• D. A gentle breeze

Answer: (B)

Impact/impulse noise consists of brief, high-energy sound events with a very rapid onset and short duration. The example involving riveting, weapon fire, or explosives fits this pattern because it creates a sudden, sharp pressure wave in a very short time, producing a large peak sound pressure level almost instantly. The other sounds are continuous or very gradual: a transformer hum is steady and ongoing, a running fan is a continuous noise source, and a gentle breeze isn’t a significant impulsive noise event. So, the riveting/weapon fire/explosives scenario best represents impulse noise.