A long uniform metallic wire of cross-sectional area carries a steady current .
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Electric Circuits · Electric Circuits
Problem
A long uniform metallic wire of cross-sectional area A carries a steady current I.
(i) Define drift velocity of free electrons in a conductor.
(ii) Using the microscopic picture of electric current, explain qualitatively how the drift velocity depends on (a) the current I, (b) the cross-sectional area A, and (c) the number density n of conduction electrons, when the other two quantities are kept constant.
(iii) If the current in the wire is kept constant, state with reason what happens to the drift velocity when (a) the area of cross-section is doubled, (b) the number density of free electrons is halved.