Question

For distant transmission of electric power, an alternating current (ac) is considered to be advantageous over direct current (dc). Why?

Answer 1

Step 1: Reason for preference of AC over DC in power transmission
Alternating current (AC) is considered advantageous over direct current (DC) for the distant transmission of electric power due to several reasons related to efficiency, cost, and ease of transformation.

Step 2: Reasons for AC being advantageous
1. Easy transformation of voltage levels:
One of the key advantages of AC over DC is the ability to easily transform the voltage level using transformers. By increasing the voltage (stepping it up) for long-distance transmission, the current can be reduced, which minimizes energy losses due to resistance in the transmission lines. Once the power reaches the destination, the voltage can be stepped down to a safe level for use. This is not as easily done with DC.

2. Lower energy losses:
When transmitting power over long distances, the energy losses due to resistance in the wires are minimized by using high-voltage AC. Since power loss (\( P = I^2 R \)) is proportional to the square of the current, reducing the current by increasing the voltage reduces the power loss significantly. This makes AC more efficient for long-distance transmission.

3. Economic benefits:
The equipment used to generate and transmit AC power (such as transformers and generators) is less expensive and simpler than the equipment needed for DC power transmission, especially for long distances. AC transmission systems are more economical and widely used across the world.

4. Less complex technology:
AC is easier to generate, distribute, and use in electrical appliances. The technology for producing and utilizing AC is more mature and widespread than for DC, especially for large-scale power distribution.

Step 3: Conclusion
For distant transmission of electric power, alternating current (AC) is advantageous over direct current (DC) because of the ease of transforming voltage, lower energy losses, economic benefits, and simpler technology involved.