Power of Electrical Circuit: Practice Problem & Solution
Two cities are $150\text{ km}$ apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is $8\text{ volt}$ and the average resistance per km is $0.5\Omega$. The power loss in the wire is: (2014)
Solution Explained:
To solve this problem, we apply the core principles of Power of Electrical Circuit. Understanding the underlying formula is key to arriving at the correct answer below:
Total resistance $R = 150 \times 0.5 = 75\Omega$. Total voltage drop $V = 150 \times 8 = 1200\text{ V}$. Power loss $P = \frac{V^2}{R} = \frac{(1200)^2}{75} = 19200\text{ W} = 19.2\text{ kW}$.
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