Certified Fire Investigator Practice Exam

How is a high explosive defined?

1. An explosive that burns rapidly

2. An explosive that detonates at supersonic speed

3. An explosive used in demolition

4. An explosive with minimal impact

The correct answer is: An explosive that detonates at supersonic speed

A high explosive is defined as an explosive that detonates at supersonic speed. This characteristic is vital because high explosives produce a shock wave that travels faster than the speed of sound. This is what distinguishes them from low explosives, which deflagrate or burn quickly but do not create a shock wave. The ability to achieve this supersonic detonation results in a powerful and destructive effect, crucial in various applications such as military munitions and certain types of construction demolitions. While other definitions of explosives might discuss their burning rates or their uses, those do not capture the fundamental aspect of high explosives, which is the speed of the reaction. For instance, an explosive that burns rapidly may be a low explosive, and an explosive used in demolition can also refer to low explosives like black powder. Therefore, the defining characteristic of high explosives is their detonation speed, making it the correct answer in this context.