yellow dwarf star in the center of the solar system diameter = 1,392,000 km, 109 times of earth’s mass = 2×1030kg, 330,000 times of earth’s 99.86% of the solar system’s total mass ¾ hydrogen, the rest is mostly helium primary source of energy in the earth
the earth receives 174 petawatts [1015 watts] from the sun 30% is reflected into space and the rest is absorbed by land, oceans, clouds etc. the total energy absorbed by earth’s atmosphere, oceans, land mass is 3,850,000 exajoules [1018 joules] per year energy entering the earth from the sun is twice the energy harnessed from all non- renewable sources of energy combined
generating electrical power by converting solar radiation into dc electricity using semiconductors that exhibit the photovoltaic effect The photovoltaic effect is the creation of voltage or electric current in a material upon exposure to light first observed by Alexandre-Edmond Becquerel in 1839
also called solar cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect made of monocrystalline silicon or polycrystalline silicon or amorphous silicon or cadmium telluride, or copper indium selenide/sulfide first built by Charles Fritts in1883 by coating the semiconductor selenium with an extremely thin layer of gold
photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon electrons are knocked loose from their atoms, and current starts flowing through the material and this electricity is captured an array of solar cells converts solar energy into a usable amount of direct current [DC] electricity
“nellis solar power plant” contains 70,000 solarpanels that will generate 25 million kilowatt-hours
“solar one”, california 1,800 sun-tracking mirrors reflect heat to a central collector
solar energy is a renewable source of energy in the presence of solar power, use of non- renewable sources of energy like petroleum can be lessened which also lessens pollution unlike others, solar energy can be harnessed and used in remote locations like mountains even though solar panels are expensive, the total amount that would be saved makes the price of the panels will seem small
solar panels are expensive solar power is inefficient in cloudy areas batteries and solar panels occupy more space solar power maintenance is a problem especially to those who doesn’t know the proper technician disposal is difficult for the batteries and solar panels when they have broken down because they contain toxic chemicals like
http://www.solarenergy-solarpower.com http://www.wikipedia.org [wikipedia] http://www.google.com [google images] the world of science, vol 10, technology of change
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