Question

In absence of external electric field the avg velocity of free electrons in a conductor at absolute zero temperature is?
A.is zero
B.doesn't depend on temperature
C.directly proportional to the sq root of temperature
D.directly proportional to temperature

Answer 1

Answer:

is zero

Explanation:

Because in the absence of electric field all the electrons are randomly oriented . The net result is that there is no regular movement of electrons in a particular direction to give rise to a current .

 

Once , the electric field is applied all the electrons are drifted towards the positive terminal and there is a net current .  

In case of semiconductors there is another method of conductivity called diffusion current . Due to external Injection of charge carriers there is excess of similar type of charge carriers . This results in a region of big charge carrier density . These similar  charges repel and move into a region of low charge carrier density .

But , as far as your question is considered in the abscence of electric field the electrons are randomly oriented . Thus , there is no current .

Hope it was helpful .