Detailed Summary
Fuels are substances that can release energy in the form of heat and light through combustion, a chemical reaction with oxygen. Fuels can be categorized as solid, liquid, or gaseous. An ideal fuel is characterized by availability, cost-effectiveness, ease of burning, high heat output, and minimal unwanted byproducts after combustion.
A fuel's efficiency is often measured by its calorific value, the amount of energy produced per kilogram during complete combustion. This section also compares common fuels like wood, coal, petrol, and LPG, illustrating the importance of understanding their properties when selecting a fuel for specific applications. The significance of fuel efficiency and environmental impact due to fuel combustion is also discussed.