Does Current Depend on Wire Diameter?

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SUMMARY

The discussion centers on the relationship between current and wire diameter, specifically addressing the drift speed and current in a 2 mm diameter wire. The key equation referenced is electron flow, expressed as I = qvA, where A represents the cross-sectional area. Participants clarify that while the cross-sectional area affects resistance, the current remains constant across wires of different diameters when connected in parallel. This is analogous to water flow in a garden hose, where a smaller diameter does not change the total flow rate if the pressure remains constant.

PREREQUISITES
  • Understanding of basic electrical concepts, including current and voltage.
  • Familiarity with Ohm's Law (I = V/R).
  • Knowledge of electron flow and drift speed in conductors.
  • Concept of resistance and its dependence on cross-sectional area.
NEXT STEPS
  • Study the principles of electrical resistance in different wire gauges.
  • Learn about the impact of wire diameter on current flow in parallel circuits.
  • Explore the relationship between pressure and flow rate in fluid dynamics.
  • Investigate the concept of drift velocity in conductive materials.
USEFUL FOR

Students in physics or electrical engineering, educators teaching circuit theory, and anyone interested in the fundamentals of electrical current and resistance in conductors.

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Homework Statement



Capture.PNG


Asking for drift speed, current in the second 2 mm diameter wire.

Homework Equations



electron flow=qvA, I=V/R, R depends on A---why doesn't current then depend on A?


The Attempt at a Solution



I can only solve it if the currents in both disks are the same, but doesn't current depend on A?
 
Last edited:
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Think of the electrical current in the same way as water in a garden hose. If the hose gets smaller does the amount of water going through vary? What would happen if I made the hose get smaller?
 
So then you're saying it wouldn't be the same in the 1mm wire as in the 2 mm wire?
 

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