What is the typical frequency of alternating current (AC) in the UK?

• A. 60 Hz
• B. 50 Hz
• C. 40 Hz
• D. 70 Hz

Answer: (B)

The typical frequency of alternating current (AC) in the UK is 50 Hz. This frequency is standardized for residential and commercial power supply, aligning with the European Union's specifications and many other parts of the world.

The choice of 50 Hz as the standard frequency dates back to historical decisions made in the development of electrical systems, where it was found to be a suitable compromise between efficiency, cost, and the performance of electrical devices. This frequency allows for effective operation of motors and transformers, providing a balance between minimizing electrical losses and ensuring compatibility with the appliances and machinery powered by the AC supply.

In contrast, frequencies like 60 Hz, often used in North America, provide different performance characteristics and compatibilities, leading to variations in electrical infrastructure across regions. Frequencies such as 40 Hz and 70 Hz are not standard in common use for power supply in the UK or any other significant markets, further validating that 50 Hz is the correct and widely accepted frequency for AC in the UK.