Energy
Simplest definition
Energy is a ability of performing work by moving or changing the position of any object. When we have energy, we can perform work. Energy is available everywhere in different forms.
Energy is a physical quantity that is capable of doing a work. Energy is transferred between various objects to perform any work.
Conservation of energy
Total energy of a closed system is constant. Energy neither can be created nor destroyed. It changes from one form to another form. The total energy of the universe also remains constant.
There are various forms of energy. One form is transformed into another form.
Types of Energy
There are various forms of energy but in general there are two major types of energy.
- Kinetic Energy: Energy associated with the motion of the particles or objects.
- Potential Energy: Energy stored with an object because of its position. Potential energy is also stored due to the work done upon the object.
Various forms of Kinetic Energy
Mechanical (Motion) Energy
Energy associated with a body in motion. Kinetic energy of body with mass (m), moving with velocity (v) can be given as –
Electromagnetic Energy
Energy associated with a magnetic force in a magnetic field due to the magnets.
Force on a moving charge (q) with velocity (v) in an electric field (E) is given by
F= qvBsinƟ
Electric Energy
Energy possessed by the charged particles that are moving.
Current, I = d(q)/dt
Force on a charge (q) in an electric field (E) = qE.
Thermal Energy
Internal energy of a substance due to the vibration of particles making up the substance. Vibration of the particles is proportional to the temperature. Kinetic Energy is proportional to the temperature.
(Kinetic Energy = 1.5kT; Where T- temperature and k is Boltzmann Constant)
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| Fire as the source of thermal energy |
Solar Energy
Energy emitted by the Sun in the form of radiations.
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| Solar Panels absorbing solar energy to generate electricity. |
Wind Energy
Energy possessed by the wind. Wind is high speed air.
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| Wind Mills |
Geothermal Energy
Heat energy of the earth coming out of the surface with water or steam.
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| Geothermal Energy Image Credits: Photos.com |
Sound Energy
Energy that is carried with the sound in the form of electromagnetic waves.
Light Energy
Electromagnetic radiation emitted from a hot and bright object.
Radiation Energy
Energy of the electromagnetic radiation.
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| Electromagnetic Waves – Sound/Light/Other Radiation waves |
Various forms of Potential Energy
Mechanical (Position) Energy
Energy associated with a body in a specific position.
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| Potential energy due the height h of an body with mass m from the earth surface. |
Magnetic Energy
Energy associated with a magnetic force in a magnetic field due to the magnets. Magnetic for
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| Magnetic Potential Energy of a magnet of mass M oriented at an angle Ɵ in Magnetic field B. |
Electrostatic Energy
Energy associated with a system where there is attraction/repulsion force between the static charged particles.Gravitational Energy – Energy of an object due to its position in a gravitational field. Energy associated with the attraction force between objects due to their mass.
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| Electric Potential Energy due the force between the charges. |
Chemical Energy
Energy possessed by the bonds between the particles of a chemical compound. Because of the chemical energy, chemical reactions take place.
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| Chemical Energy of chemicals due to their compositions |
Nuclear Energy
Energy of the nucleus (center of the particle) that binds the particles of the nucleus together.
Examples: Nuclear Fusion in the Sun and Nuclear Fission in the Nuclear power plants to generate electricity.
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| Solar energy is the created because of the nuclear fusion. |
Tidal Energy
Energy possessed by sea water in the forms of tides.
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| Tidal energy is used to turn the turbine blades to generate electricity |
Biomass Energy
Energy obtained from the mass of the living organisms.
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| Biomass Energy can be obtained by burning cow dung cake. |
Elastic Energy
Mechanical energy possessed by an object due to deformation in shape due pressure/force applied.
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| Elastic energy stored in a stretched rubber band. |
