How does the energy gap of an intrinsic semiconductor vary. When doped with a trivalent impurity?

Fill in the blanks: The doping of an intrinsic semiconductor with certain type of impurity atoms causes an .......in its electric conductivity.(decrease, increase)

How does the drift speed of electrons in a metallic conductor vary, when applied potential difference is decreased keeping temperature constant?

How does the resistivity of a conductor and a semiconductor vary with temperature? Give reason for each case.

A Group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong ?

A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?

How does the conductivity of semi-conductors varies with the rise in their temperature ?