An example of an ignition source (Heat) is which of the following?

• A. Electrical surge
• B. Solar heat
• C. Heat from chemical reaction
• D. Thermal radiation

Answer: (A)

An ignition source is anything that provides enough heat to push a material to its ignition temperature and start combustion. An electrical surge fits this best because it can produce an electric arc or spark, delivering a very intense, localized amount of heat in a tiny area. That concentrated heat can quickly ignite flammable vapors, dust, or fabrics if present.

Solar heat, while it can heat things, is usually diffuse and unreliable as a direct ignition source in many environments. Heat from a chemical reaction is energy released by the reaction itself and isn’t an external ignition source, though it can lead to ignition only if that heat transfers to nearby fuel under the right conditions. Thermal radiation transfers heat from a hot object and can cause ignition if the radiant heat is strong enough, but the immediate, localized high heat from an electrical surge is the clearest example of an ignition source.