28 Apr How can sunlight be converted into mechanical energy?
Welcome back to your physics tuition. We all know about the vast energy present inside the sun and that are present in sunlight. Do you know how it can be converted into mechanical energy? Why not ask this question to your physics tuition and your physics tuition will more than happy to give you the answer.
The sun is the biggest source of heat and light energy for us. The life exists on the earth mainly because of the sun. Today, scientists are engaged in developing new techniques through which solar energy can be utilized for the benefit of mankind.
Experiments have shown that solar energy falls on certain metals like potassium and silicon electrons are emitted from their surfaces. These electrons are known as photoelectrons and this phenomenon is called the photoelectric effect. Photoelectrons so emitted can be used to produce electric currents.
Photoelectric effect has been used for the construction of solar energy. A solar cell, in fact, is a device that directly converts solar energy into electric energy. These wafers of silicon element are used for making solar cells. Generally a 4 cm long, 2 cm broad and 0.14 mm thick silicon wafer is used for one solar cell. When sunlight falls on this wafer it gets converted into electrical energy. Each solar cell is capable of producing about one half volt of electricity.
To produce useful quantities of electric current, it is necessary to link together a great number of cells. The cells are joined together in big panels and are placed in sunlight. A panel of about 20,000 solar cells can produce 500 watts of electric power. The electricity produced may be used either immediately or to charge electric storage batteries for later use. Materials like cadmium sulfide and gallium arsenide are also being used for making solar cells.
Solar cells have several different uses. In sunny places, solar panels are used to provide boost power to telephone signals etc. Spacecrafts, space-laboratories and smaller satellites have a large number of solar cells to provide power for their transmitters and other scientific equipment.
Scientists are trying to develop better solar cells. In India, Bharat Heavy Electricals Ltd and Central Electronics Ltd are making solar cells which are being used for different applications. We hope you enjoyed this lesson from physics tuition. We will be back with more such interesting findings in our next physics tuition.