Resistance and Variation of Current in a Gradually Narrowing Ohmic Wire

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SUMMARY

The discussion centers on the behavior of current in a gradually narrowing ohmic wire. It is established that the current remains constant along the length of the wire, despite the increasing resistance due to the decreasing cross-sectional area. The drift speed of electrons increases to maintain this constant current, counteracting the effects of resistance. The key takeaway is that while resistance increases, the current does not accumulate, affirming that the current is uniform throughout the wire.

PREREQUISITES
  • Understanding of Ohm's Law
  • Knowledge of resistivity and resistance in conductors
  • Familiarity with electron drift speed in conductive materials
  • Basic principles of electric current in circuits
NEXT STEPS
  • Study the relationship between resistance and cross-sectional area in conductors
  • Explore the concept of drift velocity in conductive materials
  • Learn about the implications of Ohm's Law in varying cross-sectional areas
  • Investigate the effects of temperature on resistivity in metals
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Students studying physics, electrical engineering professionals, and anyone interested in the principles of current flow in conductive materials.

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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