(a) Define the term drift velocity of free electrons in a metallic conductor. (b) The…
PHYSICS · Subjective · CBSE · Physics · Current Electricity · Current Electricity
Problem
(a) Define the term drift velocity of free electrons in a metallic conductor.
(b) The thermal speed of electrons in a metal at room temperature is of the order of 105ms−1, while the drift velocity during ordinary conduction is only a few millimetres per second. Explain this large difference.
(c) A copper wire carries a steady current I. The wire is uniformly stretched so that its cross–sectional area becomes one-half of its original value while the number density of free electrons remains unchanged. Qualitatively state and explain how the magnitude of the drift velocity of electrons in the stretched wire compares with its initial value.