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JAMB Physics 2007 Question 25

Question 25

Alternating Current Circuits

From the diagram above, the inductive reactance and the resistance R are respectively

Diagram for this question
  1. A.10Ω and 50Ω.
  2. B.20Ω and 50Ω.
  3. C.25Ω and 51Ω.
  4. D.50Ω and 45Ω.
Show the answer and explanation

Answer: A (10Ω and 50Ω.)

Explanation

XL = 2πfL = 2π × (50/π) × 0.1 = 10 Ω. The impedance is 75 ÷ 1.5 = 50 Ω, so R = √(502 − 102) ≈ 49 Ω, about 50 Ω.