Powering Earth

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Question 18
Medium

Overhead power lines are a vital component of the national grid, facilitating the transmission of electrical energy across great distances.

a.

Explain why radio waves may be generated by these high-voltage transmission lines.

[2]
b.

Explain, with reference to the relationship between current, resistance, and power loss, why it is highly efficient to transmit electrical energy at very high voltages.

[3]
c.

A specific section of an overhead transmission line with a resistance of 7.5 Ω7.5\ \Omega7.5 Ω experiences a thermal power loss of 18.75 kW18.75\text{ kW}18.75 kW.

Calculate the electric current passing through this section of the transmission line.

[3]

Powering Earth Questions

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