Which class is a subclass requiring caution when viewed with collecting optics?

• A. Class 1
• B. Class 2
• C. Class 1M
• D. Class 4

Answer: (C)

The idea being tested is how laser safety classes account for viewing the beam through optical devices. Class 1 lasers are safe under all conditions. Class 4 is a high-hazard category. Class 2 is safe for direct eye exposure because of the blink reflex, but it becomes a concern when optics are used; however, the specific subclass that requires caution when viewed with collecting optics is Class 1M. The “M” indicates magnifying or collecting optics can concentrate the beam, making it potentially harmful even though direct viewing is safe. So, when you’re using collecting optics like magnifiers or telescopes, you must treat a Class 1M laser with caution.