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JAMB Physics 1989 Question 35

Question 35

Current Electricity

The resistance of a 5 m uniform wire of cross-sectional area 0.2 × 10−6 m2 is 0.425 Ω. What is the resistivity of the material of the wire?

  1. A.1.10 × 10−6 Ω m
  2. B.4.25 × 10−6 Ω m
  3. C.2.40 × 10−7 Ω m
  4. D.1.70 × 10−8 Ω m
Show the answer and explanation

Answer: D (1.70 × 10−8 Ω m)

Explanation

ρ = RA/L = 0.425 × 0.2 × 10−6/5 = 1.7 × 10−8 Ω m.