JAMB Physics 2010 Paper

Concept:Power is transmitted at high voltage and low current to minimize heat energy lost in the transmission wires.Explanation:Heat produced in a wire carrying current is given by $H = I^2 R t$.Here, $I$ is the current, $R$ is the resistance of the wire, and $t$ is the time.From the formula, heat loss depends on the square of the current.So, when the current is low, the heat generated in the wire becomes very small.Therefore, high voltage and low current reduce overheating of the transmission coils and wires.Answer:D. prevent overheating of the coil