Which of the following is a potential challenge when using overhead projectors?

When considering the use of overhead projectors, one of the significant challenges is related to the bulbs, which can indeed burn out. This can disrupt a presentation or lesson if a replacement bulb is not available. Overhead projectors rely on these bulbs to project images, and without functioning bulbs, the device cannot be used effectively, necessitating either a quick fix or a delay in the learning process.

The other aspects of the projector, such as energy efficiency, maintenance needs, and their role in enhancing interactive learning, tend to highlight the advantages of using this technology rather than challenges. Bulbs burning out is a specific mechanical issue that can impact the reliability of the projector during educational sessions. Therefore, understanding the lifespan and potential failure of the bulbs is crucial for effective planning and uninterrupted teaching.