What Happens to Wire Resistance When Stretched?

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SUMMARY

The resistance of a wire is determined by its length and cross-sectional area. When a wire with an initial resistance of 0.008 ohms is stretched to seven times its original length while maintaining constant volume, its resistance increases significantly. The correct calculation shows that the resistance becomes 49 times greater due to the combined effects of increased length and decreased cross-sectional area. Therefore, the final resistance of the wire is 0.392 ohms.

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  • Understanding of electrical resistance and Ohm's Law
  • Familiarity with the concepts of length, cross-sectional area, and volume in relation to materials
  • Basic knowledge of how resistance changes with physical dimensions of a conductor
  • Ability to perform calculations involving proportional relationships
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  • Study the relationship between resistance, length, and cross-sectional area in conductors
  • Learn about the formula for resistance in terms of resistivity, length, and area
  • Explore the concept of resistivity and how it varies with different materials
  • Investigate practical applications of resistance changes in electrical engineering
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Students studying physics or electrical engineering, educators teaching concepts of resistance, and anyone interested in the physical properties of materials and their electrical characteristics.

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Simple Resistance Problem...help!

Homework Statement


A wire has a resistance of 0.008 W. What will the wire's resistance be if it is stretched to seven times its original length without changing the volume of the wire? (Give answer in W.)


Homework Equations



R = Ch in V / I

The Attempt at a Solution


I thought I would just multiply 0.008 by 7? But that's not right...I know this must be so easy but for some reason I am stuck!
 
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does anyone know how to do this?
 
how resistance can be measured in watts instead omms? Maybe power which going through wire is 0.008 W and if wire will be 7 times longer then power will be 7 times smaller or resistance will be 7 times bigger. But possible that resistance will be 7*7=49 times bigger becouse, if you would have 7 times longer wire it would have 7 times bigger resistance, but becouse wire is also 7 thiner, then at all resistance will be 49 times bigger.
 

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