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What is a solar cell ? Draw its V-I characteristics. Explain the three processes involved in its working. |
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Answer» Solution :Asolar cell is basically a p-n junction which generates emf when solar radiation falls on the p-n junction. Its I-V characteriestic is shown here. (open circuit voltage) The generation of emf by a solar cell, when light falls on it, is due to following three BASIC processes : (i) Generation of e-h pairs due to incident light (PHOTON energy `E =hv gt E_(g))` close to the junction. (ii) Separation of electrons and holes due to electric FIELD of the depletion REGION. As a result electrons are swept to n-side and holes to p-side of junction. (iii) Collection of electrons REACHING the n-side and holes reaching p-side by metal contacts provided at the two sides of solar cell. 
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