What is the maximum power output for a Class 2a laser?

The maximum power output for a Class 2a laser is correctly defined as 0.5 mW. Class 2a lasers are considered low-risk because they emit visible light and have a power output threshold that does not exceed 1 mW. Lasers in this category pose minimal risk to eye safety during accidental exposure, as they are less likely to cause damage.

Other options exceed this threshold. For instance, power ratings such as 5 mW and 0.5 W are characteristic of higher-class lasers, which can present greater hazards due to their increased power and potential for eye injury. Similarly, 0.39 microW is significantly lower than the power output typical of a Class 2a laser, reinforcing the classification of these lasers based on their safety characteristics and potential exposure effects. Thus, 0.5 mW is the maximum power output that appropriately aligns with the definition and safety evaluation of Class 2a lasers.