Q 1. Explain the term energy. Distinguish between renewable and non-renewable sources of energy with suitable examples. Describe solar energy and its potential as alternative source of energy with reference of India.
Energy is the capacity of doing work. It is most important and primary input for development. All living organism needs energy for their operations .which they derived from the environment. Man has required and used the energy ever since he came on the earth. Primitive man gets energy in the form of by eating plants and animals. Later on he discovered fire and with the advancement he discovered various energy. Which he used for his domestic, industrial, transportation, agricultural, and other needs Energy is available in number of forms such as mechanical, thermal, electrical, chemical, biological energy and energy in matter. Energy is also a fundamental quantity, which in joules (J) and can be defined the work done. When a force of one Newton moves through one meter.
Natural resources that can be regenerated through rapid natural cycles are called renewable natural resources. Renewable natural resources may be inexhaustible, that is, resources that are not likely to be exhausted by human consumption such as wind, sunlight and water. Soil, groundwater, forests and living organisms are exhaustible resources, which are replenished naturally after their consumption.
However, if the renewable resources are used at a rate faster than the rate at which they are renewed, they may get exhausted. In a natural cycle, a resource is never lost; it is simply passed on from one form to another. For example, water evaporates from the water bodies to the atmosphere, forms clouds and falls down as rain. This water either collects as groundwater or is returned to rivers and oceans.
Non-renewable resources include coal, petroleum, natural gas, mineral ores, diamonds, etc. These resources were formed in millions of years and hence will get exhausted, eventually. Judicious use of these resources would help in making them last longer.
Solar energy is the energy produced and radiated by the sun, more specifically , the sun's energy that reaches to the earth. Solar energy which is the primary source of all kind of energy on the earth, originates in the sun as a result of thermo nuclear fusion reaction... Sun can be considered as a large sphere containing helium gas , which is continuously producing hydrogen through fusion reactions and liberating a large amount of heat energy.... This energy is radiated by sun in the form of electromagnetic radiations of which 99% having their wavelengths in the range of .4 micro metre. Solar power reaching the top of earth's surface is 10 ^17 watts and that on earth's surface is 10^16 watts , while total power requirement of the world is 10 ^13 watts. So if we can use only 5% of this energy , it will be 50 times more than our requirement . Solar radiation can be converted into other forms of energy , such as heat , electricity etc.
Solar energy keeps the temperature of earth above that in colder space , causes air currents in atmosphere and water currents in oceans , causes the water cycle and helps in photosynthesis in plants
As our reserves of coal , oil, gas will last only for few more years and nuclear energy involves considerable hazards , solar energy can be a very important source of energy ... Since sun can radiate at this constant rate for over a few billion years , it can be considered as a in exhaustible source of energy