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 potenti,ll 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 c

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 potenti,ll 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» Solution :(i) Conductivity of semi-conductors INCREASES when LIGHT falls on them and certain impurities are added to them. (ii) Materials like SILICON, Selenium, CADMIUM sulphide and Copper sulphide act as semi-conductors.