Answer:
Check the explanation
Step-by-step explanation:
(a) When the electric field is applied to the ends of the wire, electrons move through the wire because the resistance of the wire is less than the resistance of the surrounding air. Resistance is the obstruction to the flow of electrons hence electrons flow through the path having minimum resistance.
(b) As the thermal energy increases, Kinetic energy of electrons as well as that of positive ions also increase. Hence the mean time between collisions of electrons with ions is reduced due to movement of ions also. That is why Resistance of the wire increases.