What aspect does electrical efficiency measure?

Electrical efficiency measures the overall effectiveness of converting energy from one form to another, typically from electrical energy into useful work or heat. It is a critical concept in evaluating how well an electrical system utilizes the power it consumes. High efficiency indicates that a large portion of the electrical energy is effectively transformed into the desired output, minimizing waste and reducing operational costs.

Understanding electrical efficiency allows engineers and technicians to design systems that optimize energy use, which is crucial for both economic and environmental reasons. For instance, if an electric motor has a high efficiency rate, it means it draws less energy for the same performance output compared to a motor with lower efficiency.

The other choices address related aspects but do not capture the essence of efficiency: the cost of electricity focuses on financial implications, the quality of components pertains to reliability and durability, and duration of operation relates to how long a system functions rather than how effectively it converts energy. Thus, the correct answer highlights the core principle of efficiency itself.