Physics · Electrical energy and power, electrical resistivity and conductivity
If a wire is stretched to make it Ionger, its resistance will:
If a wire is stretched to make it \( 0.1 \% \) Ionger, its resistance will:
- A. Increase by \( 0.2 \% \)
- B. Decrease by \( 0.2 \% \)
- C. Decrease by \( 0.05 \% \)
- D. Increases by \( 0.05 \% \)
Step-by-step solution
Resistance R = ρL/A. When stretched, volume constant: L' = L(1+ε) with ε=0.001, so A' = A/(1+ε). Then R' = ρL'/A' = ρL(1+ε) / (A/(1+ε)) = R(1+ε)^2 ≈ R(1+2ε). So ΔR/R ≈ 2ε = 0.2% increase.
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