Question

Answer the following question.

DC current flows in a metal piece of the non-uniform cross-section. Which of these quantities remains constant along the conductor: current, current density, or drift speed?

Answer 1

• Drift velocity and current density will change depending on the area of the cross-section, whereas current will remain constant.
• In a metal piece with a non-uniform cross-section through which DC current flows, the quantity that remains constant along the conductor is the current.
• This is because the principle of conservation of charge ensures that the same amount of charge passes through every cross-section of the conductor per unit time, regardless of changes in its cross-sectional area