Physics – 4.2.4 Resistance | e-Consult
4.2.4 Resistance (1 questions)
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Solution:
- Initial resistance formula: R = ρL/A. We know R = 3.0 Ω, L = 0.15 m, and A = 2 x 10-6 m2. We can use this to find the resistivity (ρ): 3.0 Ω = ρ(0.15 m) / (2 x 10-6 m2). Therefore, ρ = (3.0 Ω)(2 x 10-6 m2) / (0.15 m) = 4 x 10-5 Ωm.
- New length: The length is doubled, so the new length (L') is 30 cm = 0.3 m.
- Calculate the new resistance: R' = ρL' / A = (4 x 10-5 Ωm)(0.3 m) / (2 x 10-6 m2) = 0.6 Ω.
Answer: The new resistance is 0.6 Ω.