In a lighting system, an optical source refers to

• A. A diffuse ambient lamp
• B. A single independently mounted light emitting component
• C. A reflective surface behind a lamp
• D. A pair of LEDs wired in series

Answer: (B)

An optical source is the element that actually emits light. It is the single, independent light-emitting component that can be mounted and powered by the system. This makes the description a lone, self-contained emitter like an LED or lamp, rather than a passive part or a non-emitting arrangement. A diffuse ambient lamp, for example, is a type of lamp but doesn’t capture the idea of the source itself as an independent emitter. A reflective surface behind a lamp doesn’t emit light at all. A pair of LEDs in series are two emitters working together, which is not the solitary emitter the term “optical source” is pointing to in this context.