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What is the principle of solar cell? Write its advantages and disadvantages

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#### Solution

PRINCIPLE :-

In photoelectric effect when radiation is incident on a metal surface electron are ejected. In photovoltaic effect, certain materials being exposed to radiation generates electron hole pairs available for conduction. As a result a voltage is developed across the material. The radiation energy E= hϑ is required to be greater then the band gap energy Eg of the material. This is a phenomenon in which light energy is converted into electrical energy.

ADVANTAGES :-

⦁ Environmentally friendly.

⦁ No noise, no moving parts.

⦁ No emission.

⦁ Minimum maintenance required.

⦁ Long lifetime, up to 30 years.

⦁ PV operator even in cloudy weather condition. Disadvantages:-

⦁ PV cannot operate without light .

⦁ High initial costs that overshadow the low maintenance costs and lack of fuel costs.

⦁ Large area needed for large scale applications.

⦁ PV generates direct current special DC appliances or an inverter are needed.

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