Electric power is transmitted over long distances through cables. These cables have resistance, and power is lost as heat according to the formula P_loss = I² R, where I is the current and R is the resistance of the cable. To minimize this power loss for a given amount of power being transmitted (P = V I), the voltage (V) is stepped up to a very high level by transformers at the power station. This high voltage means the current (I) required to transmit the same power is much lower (I = P/V). A lower current significantly reduces the power loss (I²R) in the transmission lines. At the receiving end, transformers step the voltage back down for safe use in homes and factories.
Transformers are used in between the electric power stations and homes or factories in order to
Asked in UPSC CAPF 2011 · Topic: Electric Current (Electrical Power and Energy, Joule heating effect)
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Answer: A. minimize the power loss in transmission cables
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