(i) Semiconductors are useful as electronic devices because

       They are very abundant in nature

       They are all good conductors

       They have a very high melting point

        Their electrical conductivity can be controlled by the addition of impurities

        Their electrical conductivity can be controlled by a variation in the temperature

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(ii) The magnitude of the electronic bandgap in a solid is primarily determined by

      The temperature

       The number of free electrons in the material

       The nature and strength of the chemical bond in the material  

        The type of doping in the material

        Will decrease when we apply a positive voltage

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(iii) The number of intrinsic carriers in a semiconductor   

      Will be determined by the temperature and the bandgap of the material

       Is always greater than the extrinsic concentration

       Is always less than the extrinsic concentration  

       Is determined by the doping level in the material

       Will determine the conductivity of the material  

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iv) When doping a semiconductor n type, the bandgap of the material will:

      Increase

       Decrease

       Remain the same

        Will decrease when we apply a negative voltage

        Will decrease when we apply a positive voltage

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