Resistance and Variation of Current in a Gradually Narrowing Ohmic Wire

AI Thread Summary
In a gradually narrowing ohmic wire, the current remains constant despite the increase in resistance due to the reduced cross-sectional area. The confusion arises from the relationship between resistance and current, where an increase in resistance does not lead to an accumulation of charge in the wire. Instead, the drift speed of electrons increases to maintain a constant current throughout the wire. The discussion highlights that while resistivity increases, the current itself does not vary along the length of the wire. Understanding this relationship is crucial for analyzing current flow in varying cross-sectional areas.
bennyq
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Homework Statement



A current-carrying ohmic metal wire has a cross-sectional area that gradually becomes smaller from one end of the wire to the other. How does the current vary along the length of the wire?

Homework Equations



a. It increases.
b. It remains constant.
c. It decreases.


The answer give is (A).. I am a bit confused, as my understanding is the resistance will increase in the wire, but the current should be constant through it as to not accumulate any charge in the wire.. So the wires resistance increases, and the drift speed of the electrons increase to maintain the constant current through the wire?? Do you think the questions is meant to ask, how does the driftspeed/resistance vary along the length?
 
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You are right, the current is the same along the wire. The resistivity increases.

ehild
 
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