What is the safe exposure time for Class 2a lasers?

Class 2a lasers are classified as low-risk under the laser safety standards because their output power is limited to a maximum of 1 milliwatt and they emit visible light. The significance of this classification is that the human eye has a natural aversion response, which typically causes individuals to blink or turn away if they inadvertently look at the beam. This aversion response provides a safety margin, allowing for a limited exposure time without causing eye injury.

The safe exposure time for Class 2a lasers, which is often cited as around 10 seconds, denotes the threshold duration an individual can be exposed to the beam before risking potential harm. This takes into account the eye's reflexive actions that occur in response to sudden bursts of bright light.

In contrast, the other options reflect durations that exceed the established safety limits for Class 2a lasers, meaning they pose a greater risk of eye damage. The specified safe exposure time is critical for maintaining compliance with safety standards in environments where laser use is prevalent.