The quantitative property transferred to a body or a physical system, recognizable in the performance of work is known as energy. It can be in the form of heat and light. Energy is a conserved quantity that is it can neither be converted nor destroyed. It can only be converted from one form to another and this is known as the law of conservation of energy. The SI unit of energy is the joule. It is defined as the energy transferred to an object by the work of moving it a distance of one metre against a force of one newton.
There are different types of energy such as electrical energy, chemical energy, mechanical energy, thermal energy, nuclear energy etc. Moreover, all living organisms constantly take in and release energy.
Electrical energy is energy due to of movement of electrically charged particles. Simply we can say electrical energy refers to the energy that has been converted from electric potential energy. It is supplied by the combination of electric current and electric potential that is delivered by an electrical circuit. At the point where electric potential energy is converted to another type of energy, it stops being electric potential energy. Thus, we can say all electrical energy is potential energy before it is delivered. Electrical energy once converted from potential energy, it can always be called another type of energy such as heat, light, motion etc.
Chemical energy is the energy released when a chemical substance undergoes a chemical reaction and transforms into another substance. Batteries, food, and gasoline are some of the examples of storage media of chemical energy. Making chemical bonds and breaking them involves energy, which may be either absorbed by or evolved from a chemical system.
If the initial and final temperature is the same then the energy that can be released or absorbed because of a reaction between chemical substances will be equal to the difference between the energy content of the products and the reactants. From the bond energies of the reactants and products, this change in energy can be estimated.
The sum of potential energy and kinetic energy is called mechanical energy. If an isolated system is subject only to conservative force then the mechanical energy is constant. This is the principle of the law of conservation of energy. If an object moves in the opposite direction of a conservative net force then the potential energy will increase. Moreover, if the speed of the object changes, then the kinetic energy of the object also changes. In all real systems nonconservative forces, such as frictional forces, will be present. If they are of negligible magnitude then the mechanical energy changes little. In the case of elastic collisions, the kinetic energy is conserved, but in the case of inelastic collisions, some mechanical energy may be converted into thermal energy.
Devices such as an electric motor convert electrical energy to mechanical energy. Similarly, an electric generator converts mechanical energy into electrical energy whereas a heat engine converts heat to mechanical energy.
Thermal energy also called heat energy is produced when a rise in temperature causes the atoms and molecules to move faster and collide with each other. Or in other words, we can say that thermal energy is the energy that comes from the temperature of the heated substance. When a substance heats up, the temperature rises and this makes the particles move faster and bump into each other. The hotter the substance, the particles move faster, and the higher its thermal energy.
The form of energy released from the nucleus, the core of atoms, made up of protons and neutrons is known as nuclear energy. Nuclear energy can be produced in two ways. One is fission and the other one is fusion. When nuclei of atoms split into several parts it is known as fission and when nuclei fuse it is known as fusion.
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Fossil fuels are the largest sources of energy for electricity generation. Natural gas was the largest
source about 38% of U.S. electricity generation in 2021.
Electricity cannot itself be stored on any scale, but it can be converted to other forms of energy which can
be stored and later reconverted to electricity on demand. Storage systems for electricity include battery,
flywheel, compressed air, and pumped hydro storage.
Chemical energy originates in the interactions of atoms and molecules. Generally, there is a
rearrangement of electrons and protons, called a chemical reaction, which produce electric charges. The
law of Conservation of Energy stipulates that energy can be transformed or converted but never
Boiling water on a stove is an example of thermal energy. Thermal energy is produced when the atoms
and molecules in a substance vibrate faster due to a rise in temperature