Semi-conductors are certain type of metals which allow only partial current to pass through them in one direction only. In a solar cell, the pieces (wafers) of semi-conductor materials containing impurities are so arranged that potential difference develops between two regions of the semi-conductors when light falls on it. A lead storage battery is connected in the circuit which gets charged and can be used as and when desired. (i) How does conductivity of semi-conductors increases ? (ii) Name any four materials which act as a semiconductor.

Semi-conductors are certain type of metals which allow only partial cu

1.	Semi-conductors are certain type of metals which allow only partial current to pass through them in one direction only. In a solar cell, the pieces (wafers) of semi-conductor materials containing impurities are so arranged that potential difference develops between two regions of the semi-conductors when light falls on it. A lead storage battery is connected in the circuit which gets charged and can be used as and when desired. (i) How does conductivity of semi-conductors increases ? (ii) Name any four materials which act as a semiconductor.
Answer» (i) The conductivity of semiconductors increases when light falls on them and certain impurities are added to them. (ii) Materials like Silicon, Selenium, Cadmium sulphide and Copper sulphide acts as semiconductors.

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