Two substances are identical except that the electron mean free time for substance A is twice the electron mean free time for substance B.If the same electric field exists in both substances the electron drift speed in A is:
A)the same as in B
B)twice that in B
C)half that in B
D)four times that in B
E)one fourth that in B

Question

Quizplus · Accepted Answer

The electron drift speed is directly proportional to the electron mean free time. Therefore, if the electron mean free time in substance A is twice that in substance B, the electron drift speed in A will be twice that in B.

Two Substances Are Identical Except That the Electron Mean Free