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JAMB Physics 2005 Question 18

Question 18

Current Electricity

The resistance of a piece of wire of length 20m and cross-sectional area 8 × 10−6m2 is [Resistivity of the wire = 4 × 10−7Ωm]

  1. A.1.0Ω.
  2. B.10.0Ω.
  3. C.0.5Ω.
  4. D.5.0Ω.
Show the answer and explanation

Answer: A (1.0Ω.)

Explanation

R = ρL/A = 4 × 10−7 × 20 ÷ 8 × 10−6 = 1.0 Ω.