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JAMB Physics 1992 Question 40

Question 40

Electrical Energy and Power

Which of the following apparatus will require the smallest fuse rating for its protection?

  1. A.60W, 240V
  2. B.60W, 40V
  3. C.40W, 12V
  4. D.40W, 5V
Show the answer and explanation

Answer: A (60W, 240V)

Explanation

Current I = P/V: 60/240 = 0.25 A, 60/40 = 1.5 A, 40/12 ≈ 3.3 A, 40/5 = 8 A. The smallest current needs the smallest fuse.