Question

Given a current carrying wire of non uniform cross section. Which of the following is constant throughout the length of the wire?

• A. current, electric field and drift speed
• B. drift speed only
• C. current and drift speed
• D. current only

Answer 1

Answer: (D)

current only

Answer 2

In steady state condition the current at each cross-section will be the same. Drift velocity and electric field depend on the current density, $\bar{M}$ which varies from one crosssection to another.