Energy

The simple answer to this question is the ability or capacity to perform work. But in physics, energy is a property of object which can be transfer to other objects or converted in to different forms. It is not possible to give a general description of energy because of its different forms.

We are live in a world having energy everywhere. Energy is inside as well as outside the body. For instance Air, water, soil, fire and sun are various sources of energy. The source which are extensively used are conventional source. Which are not used excessively are non-conventional source of energy.

Conventional sources fulfill the major part of the demand of energy. Non conventional are alternate sources of energy. Hydro energy, biomass, natural gas, and fossil fuels are conventional sources whereas solar energy, tidal power, and nuclear power, wave energy and geothermal energy are some of the non-conventional sources of energy.

Unit of energy

For the Quantitative discussion we need units to measure the energy. The energy of a body is define as its capacity for doing work. The unit of energy is same as that of work i.e. “Joule” In SI system and “erg”  in the CGS system. joule symbolic representation is J.

Energy (J)  =  Force(N) *Distance(M)

1 joule is define as the energy supply by the force of 1 Newton to move an object through a distance of 1 metre. Joule is dimensionally equivalent to 1 Newton metre.

Sometimes energy is measure in terms of power.  Practically energy and power are different but power consumed energy. So If the power of an electric heater is 1 kilowatt and it works for an hour,  it consumes one kilowatt-hour (kWh) of energy.

In discussion of energy production and consumption, the Unit barrel of oil  equivalent and ton of oil equivalent are often use. The imperial/US units for Energy foot – pound force (1.3558J), the British thermal unit (btu).  Which has various value in the region of 1055J, the horsepower-hour(2.6845 MJ), and the gasoline gallon equivalent (about 120 MJ).