Calculate resistance from resitivity

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SUMMARY

The discussion focuses on calculating electrical resistance using the formula R = pL/A, where R represents resistance, p is resistivity, L is length, and A is cross-sectional area. The user initially calculated a resistance of 152.789 Ohms but was informed that the precision of the input values limits the precision of the output. Specifically, with resistivity and diameter provided to one-digit accuracy, the resistance should be reported with a maximum of two significant figures, resulting in an acceptable value of 150 Ohms.

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  • Understanding of electrical resistance and Ohm's Law
  • Familiarity with the formula R = pL/A
  • Basic knowledge of significant figures in scientific calculations
  • Concept of cross-sectional area in cylindrical conductors
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Homework Statement



upload_2015-4-15_9-50-55.png

Homework Equations


R = pL/A

The Attempt at a Solution



R(a) = 2x10^-4(0.15)/[pi(0.0005/2)^2] = 152.789 [Ohms]

It is slightly off. Is there a subtle point that I've missed?

Thank you very much.
 
Last edited:
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No, except that when they give you the resistivity and the diameter in 1 digit accuracy each, you cannot return a resistance with 6 digits precision. Because the first digit is a 1, you return two digits. That means 1.5 x 102, but 150 is acceptable generally.
 
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I see, thank you very much.
 

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