Energy: Definition, and Types

What is Energy?

Energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. There are, moreover, heat and work i.e., energy in the process of transfer from one body to another.

Energy is the ability to do work. Scientists define energy as the ability to do work. Modern civilization is possible because people have learned how to change energy from one form to another and then use it to do work.

People use energy to walk and bicycle, to move cars along roads and boats through water, to cook food on stoves, to make ice in freezers, to light our homes and offices, to manufacture products, and to send astronauts into space.

There are many different forms of energy, including

  • Heat
  • Light
  • Motion
  • Electrical
  • Chemical
  • Gravitational

These forms of energy can be grouped into two general types of energy for doing work:

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  • Potential or stored energy
  • Kinetic or working energy

Energy can be converted from one form to another. For example, the food a person eats contains chemical energy, and a person’s body stores this energy until he or she uses it as kinetic energy during work or play. The stored chemical energy in coal or natural gas and the kinetic energy of water flowing in rivers can be converted to electrical energy, which in turn can be converted to light and heat.

Energy sources can be categorized as renewable or nonrenewable

There are many different sources of energy, which can be divided into two basic categories:

Renewable and nonrenewable energy sources can be used as primary energy sources to produce useful energy such as heat, or they can used to produce secondary energy sources such as electricity and hydrogen.

Energy Formula:

Energy formulaEnergy = Power x Time
Kinetic energy formulaK.E. = 1/2 mv2
Potential energy formulaU=mgh
Gravitational potential energy formulaΔPEg = mgh
Conservation of energy formulaK1+U1 =K2+U2
Mechanical energy formula(Em=K+U) Mechanical energy = kinetic energy + potential energy
Elastic potential energy formulaElastic potential energy = force × displacement.
Internal energy formulaΔU  = Q + W
Spring potential energy formulaString potential energy = force × distance of displacement.
Electric potential energy formulaUE = k (q1q2/r)

Different Types of Energy

Many types of energy exist, but they all fall into two basic types of energy:

  • Potential or stored energy
  • Kinetic or working energy

Kinetic Energy

All moving objects have kinetic energy. Kinetic energy is the energy an object has because of its motion. It can define as the work needed to accelerate a body from rest to its current velocity. Kinetic energy depends on the mass of the object.

When the velocity or the mass of a body increases, the kinetic energy also increases. The kinetic energy can be either zero or positive. Some of the examples of kinetic energy are moving cars, moving the ball, the river flowing, an athlete running, and a satellite revolving in an orbit.

1. Radiant Energy

Radiant energy is electromagnetic energy that travels in transverse waves. Electromagnetic energy is a type of energy in which energy is emitted through electrical or magnetic waves travelling through space.

These waves do not require a medium and travel through empty space at the speed of light. It has vibrations of both electricity and magnetism. Some of the examples of electromagnetic waves are X-rays, microwaves. Radio, gamma rays, and ultraviolet rays are examples of electromagnetic waves.

2. Thermal Energy

Thermal energy is also known as Heat energy. This is a type of energy in which the object gets energy due to the movement of the molecules within the object. As the movement of these molecules becomes faster, more heat is produced.

Heat energy on Earth is from the sun above. This energy can transfer only by convection, conduction, and radiation. It is difficult to convert heat energy into other forms. Some of the examples of heat are gas stove burners, a hot cup of coffee and when u rub your hand together, heat energy is produced.

3. Motion Energy

Motion energy is energy stored in the movement of objects. The faster they move; the more energy stored. It takes energy to make an object moving, and energy is released when an object slows down. The wind is an example of motion energy.

A dramatic example of motion energy is a car crash—a car comes to a total stop and releases all of its motion energy at once in an uncontrolled instant.

4. Sound Energy

Sound energy is a type of energy in which associated with matter vibrations. Sound energy needs a medium to travel and produces low levels of energy. Due to this property of sound, there is no sound in space. 

The measurement of these waves depends upon its intensity and pressure. Sound travels fastest through a liquid. Sound of vehicles, wind chimes, laughing, crying, water falling, boiling, whistles, guitar all are examples of sound energy.

5. Electric Energy

Electric energy is a type of energy due to the movement of electric charge and can be commonly called electricity. The origin is from electromagnetic forces. When this electrical energy flows, a little bit of heat energy is generated. Electric heaters, appliances, lights, fans, television, and all use electrical energy.

Potential Energy

Potential energy is a type of energy possessed by an object due to its virtue or position. In simpler terms, potential energy is something that is present but does not do any work. It is the stored energy and can convert to kinetic energy.

Some of the examples of potential energy are holding a pen up, car on a hilltop, a stretched rubber band, a glass of milk, and fruit hanging from a tree.

1. Chemical Energy

Chemical energy is a type of energy store in chemical compounds and release during a chemical reaction. In most of these reactions, heat energy is the byproduct. Chemical energy is the most common form of energy.

It comes in different forms and can constantly change its form. The food that we eat, all battery-powered devices, combustion of oil, fuel, and gas and electricity are some of the examples of chemical energy.

2. Mechanical Energy

The mechanical energy is the sum of the kinetic energy, or energy of motion, and the potential energy, or energy stored in a system by reason of the position of its parts.

Mechanical energy is constant in a system that has only gravitational forces or in an otherwise idealized system that is, one lacking dissipative force, such as friction and air resistance, or one in which such forces can be reasonably neglected.

3. Nuclear Energy

Nuclear energy is a type of energy inside the atom in the nucleus. Each object around us is made up of an atom. There is a lot of energy in these atoms. On certain grounds, these atoms release energy which can be harmful and useful to mankind.

This energy can be used to generate electricity, boil water to create steam and even explode a nuclear bomb.

4. Atomic Energy

Atomic Energy is produced when you split atoms. A tremendous amount of energy is released when this happens. Atomic bombs, nuclear power plants, nuclear submarines, and the sun are some of the examples of Atomic Energy.

5. Gravitational Energy

Gravitational energy is a type of energy possessed by an object when it is moved against gravity. This is mainly caused due to the pull of gravity. The higher the object, the higher the gravitational energy.

The force of gravity of an object depends upon the mass of the object. Some of the examples of gravitational energy are water stored in a dam, rocks at the top of a hill, and a parachute.

6. Solar Energy

Solar energy is the energy that is received from the sun. It is the most abundant and the most renewable form of energy. If the entire populations efficiently use this solar energy for all purposes no other form of energy needs to be utilized.

It is a free source of heat and light energy. Solar panels, cells, torches, lights, fans, solar farms, and solar stations are some of the variations that use the sun as their medium.

7. Magnetic Energy

Magnetic energy is a type of energy stored in the magnetic fields in magnets. All magnets are examples of magnetic energy.

8. Surface Energy

Surface energy is a type of energy that is present by virtue of existence. This types of energy is present in a stretched rubber band, stagnant water, etc. in simple terms when 2 liquids come in contact with each other, surface tension is created.

This is the surface energy. Usually, in solids, surface energy combines with elastic energy. If an insect floats on the water then it is because of the surface energy.

9. Wind Energy

Wind energy is the energy of the winds. This is a green, renewable, and affordable source of energy that is utilizing for a long period of time. Wind energy is utilized in the form of windmills and turbines which convert the kinetic energy of the wind into mechanical energy and further into electric energy.


What is Energy?

Energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. There are, moreover, heat and work—i.e., energy in the process of transfer from one body to another.

What is the Definition of Energy?

Energy, in physics, is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. After it has been transferred, energy is always designated according to its nature.

What Is the Formula for Energy?

The formula that links energy and power is Energy = Power x Time. The unit of energy is the joule, the unit of power is the watt, and the unit of time is the second.

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