What is a detonation?

• A. A deflagration in which a flame front travels subsonically.
• B. A detonation is a shock wave that moves faster than the speed of sound.
• C. A slow chemical explosion.
• D. A nuclear explosion.

Answer: (B)

Detonation is a combustion wave driven by a leading shock that moves faster than the speed of sound in the mixture. The shock compresses and heats the fuel–oxidizer, causing the chemical reaction to ignite behind the shock as the wave propagates. This supersonic, shock-driven process distinguishes it from a deflagration, which is subsonic and spreads by heat and mass transfer from the flame front. The other descriptions don’t match: a slow chemical explosion isn’t capturing the shock-driven, supersonic nature, and a nuclear explosion involves nuclear reactions, not chemical detonation.