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JAMB Physics 2020 Objective — Question 19

Question 19 of 40 from the Joint Admissions and Matriculation Board (JAMB) Physics 2020 Objective paper, with the correct answer and a full explanation.

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19. If a current of 4A is passed through a thin cable for two hours, how much electrical energy will be converted to heat energy, given that the electrical resistance of the cable is 10 ohms?

  • A. A. 4.25MJ
  • B. B. 2.15MJ
  • C. C. 1.95MJ
  • D. D. 1.15MJCorrect

Explanation

H = I^2Rt = 4^2 x 10 x (2x3600)s = 16x10x7200 = 1,152,000J ≈ 1.15MJ.

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