WAEC Physics 2013 Objective — Question 45
Question 45 of 50 from the West African Examinations Council (WAEC) Physics 2013 Objective paper, with the correct answer and a full explanation.
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A coil of inductance 0.12H and resistance 4Ω, is connected across a 240V, 50Hz supply. Calculate the current through it. [π=3.14]
- A. 6.3 ACorrect
- B. 33.3 A
- C. 37.2 A
- D. 40.0 A
Explanation
XL = 2πfL = 2×3.14×50×0.12 = 37.68Ω. Impedance Z = √(R²+XL²) = √(4²+37.68²) ≈ 37.9Ω. Current I = V/Z = 240/37.9 = 6.33A ≈ 6.3A.
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