Question

The substance which gives heat and light after combustion are called?

Answer 1

Combustion, often known as burning, is a high-temperature exothermic redox chemical process in which a reductant (fuel) reacts with an oxidant (typically atmospheric oxygen) to create oxidized, frequently gaseous products in a mixture known as smoke. Because a flame is only visible when components undergoing combustion vaporize, combustion does not always result in fire, but when it does, a flame is a distinctive indication of the process. While the activation energy must be overcome to begin combustion (for example, lighting a fire with a lighted match), the heat from a flame may supply enough energy to keep the process going.

Complete answer:
Combustible is a term used to describe a material that may burn. It's known as fuel. When a magnesium ribbon is heated, it begins to burn. When a magnesium ribbon burns, it reacts with oxygen in the air to generate magnesium oxide, which produces heat and light. A combustible material is one that produces heat and light following burning. Wood, coal, kerosene, gasoline, LPG, and other fuels are examples.
A combustible substance is one that can burn (combust) in the presence of air. In other words, a combustible substance takes some effort to ignite, but a flammable material ignites instantly when exposed to flame. The degree of flammability or combustibility in air is primarily determined by the material's volatility, which is linked to its composition-specific vapour pressure, which varies with temperature. By expanding the surface area of the substance, the amount of vapour generated may be increased, resulting in a mist or dust. Take, for example, wood. Finely split wood dust can burn explosively, resulting in a blast wave. A piece of paper (made of wood) may readily catch fire.
Hence Combustible substances will be our answer.

Note:
The mass of the combustion products equals the mass of the combustible material and the mass of the oxygen required for combustion (ash, water, carbon dioxide, and other gases). One of the early pioneers in these ideas was Antoine Lavoisier, who declared, "Nothing is lost, nothing is generated, everything is changed," which became known as the rule of conservation of mass.