Which of the following is an example of an energy-efficient device?

A fluorescent bulb is an example of an energy-efficient device because it uses less electricity to produce the same amount of light compared to traditional incandescent bulbs. Fluorescent bulbs work by utilizing a gas that fluoresces when electricity is applied, resulting in improved energy conversion and reduced waste heat. This allows them to operate at a much lower wattage while still providing adequate illumination, which can significantly lower energy consumption and costs over time.

In contrast, incandescent bulbs consume more electricity and convert much of that energy into heat rather than light, making them less efficient. Electric heaters, while effective for generating heat, generally consume a large amount of energy to operate and do not qualify as energy-efficient devices. Standard refrigerators, while they may have energy-efficient models available, can vary widely in their energy consumption, and many older models are not designed to minimize energy use, making them less efficient overall compared to modern alternatives like energy-efficient fluorescent bulbs.