Current density, resistance and resistivity problem

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SUMMARY

The discussion centers on a problem involving a 10.71 V battery connected to a resistive strip with three sections of varying conductivities. Participants clarify that the current density (J) across all sections is equal due to the conservation of charge, despite differing conductivities. The user initially miscalculated the current density for the third section, leading to incorrect conductivity values for the first two sections. The issue was resolved by correctly interpreting the graph values, which were in the format of x10^3 rather than x10^-3.

PREREQUISITES
  • Understanding of current density (J) and its relationship with conductivity (σ) and electric field (E).
  • Familiarity with Ohm's Law and the concept of electric circuits.
  • Knowledge of resistive materials and their properties, including conductivity.
  • Ability to interpret scientific graphs and data representations.
NEXT STEPS
  • Review the principles of current density and its implications in electrical circuits.
  • Study the relationship between conductivity and electric field in different materials.
  • Learn how to accurately read and interpret scientific graphs and data formats.
  • Explore the conservation of charge in electrical systems and its applications in circuit analysis.
USEFUL FOR

Students and professionals in electrical engineering, physics enthusiasts, and anyone involved in circuit design or analysis who seeks to deepen their understanding of current density and conductivity in resistive materials.

ctpengage
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In a problem it states that:

A 10.71 V battery is connected to a resistive strip that consists of three sections with the same cross-sectional areas but different conductivities.

In the solution to the problem it stipulates that the current density of the three sections are equal. Where in the above statement does it imply that.
 
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please answer guys
 
Think about what the definition of current density is. Also, is current conserved?
 
charge and current are reserved.

I am also working on this problem, but when I calculate the current density from the third section (since I am given the third section's conductivity) I am getting the wrong answer for the conductivities of parts 1 and 2..

charge density = conductivity of part 3 * electric field of part 3

J = \sigma * E3

The current of the battery flows through the 3 part resistive strip to the negative terminal of the battery.

the distance on the strip is defined as 0 at the positive connection side of the strip and 9.12mm at the negative side of the strip.

I then use the equation

conductivity = J / E per part

to calculate conductivity of parts 1 and 2.

Im getting this wrong so I am guessing calculating J is wrong. Can someone steer me in the right direction?
 
I figured it out!

I was reading the graph values wrong in that it was x10^3 and not x10-3
 

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