Q. A steady current is set up in a metallic wire of non-uniform cross-section. How is the rate of flow of electrons ($R$) related to the area of cross-section ($A$)?
A) $R \propto A^{- 1}$
B) $R \propto A$
C) $R \propto A^{2}$
D) $R$ is independent of $A$
Explanation
(a) Rate of flow of electrons in a conductor is low but number density of free electrons in a conductor is very high. The drifting of electrons over the entire length of the conductor contributes to the current throughout the conductor
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.