Question
22 Which of these must be present for a fire to exist? A A chemical chain reaction B An electrical current C A water source D An incombust ible material
Answer
4.2
(179 Votes)
Rhian
Elite · Tutor for 8 years
Answer
A chemical chain reaction
Explanation
## Step 1: Understanding the question and the options provided. The question asks for the essential elements needed for a fire to exist. ## Step 2: Recall the fire triangle concept. The fire triangle is a model for understanding the necessary ingredients for most fires. It consists of three elements: heat, fuel, and an oxidizing agent (usually oxygen). ## Step 3: Evaluate the options based on the fire triangle concept. ### Option A: A chemical chain reaction. This is an integral part of the fire process. The heat source ignites the fuel, and then oxygen combines chemically with the fuel in a process known as oxidation. This process is a chemical chain reaction and is responsible for maintaining and propagating a fire over time.### Option B: An electrical current. An electrical current can be a source of heat, but it is not a necessary element for a fire to exist. ### Option C: A water source. Water is used to extinguish fires, not to create them. Therefore, it is not a necessary element for a fire to exist.### Option D: An incombustible material. An incombustible material is one that does not burn, so it cannot be a necessary element for a fire to exist.