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JAMB Physics 2007 Objective — Question 26

Question 26 of 50 from the Joint Admissions and Matriculation Board (JAMB) Physics 2007 Objective paper, with the correct answer and a full explanation.

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A 40kW electric cable is used to transmit electricity through a resistor of resistance 2.0 ohm at 800V. The power loss (internal energy) is

  • A. 5.0x10^2 W
  • B. 5.0x10^3 WCorrect
  • C. 5.0x10^4 W
  • D. 5.0x10^5 W

Explanation

I = P/V = 40,000/800 = 50A. Power loss = I2R = 50^2 x 2 = 5000W = 5.0x10^3 W.

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