For solar panel inspection, the minimum irradiance required is closest to:

• A. 600 W/m^2
• B. 900 W/m^2
• C. 1200 W/m^2
• D. 150 W/m^2

Answer: (A)

Irradiance sets how much light energy is driving the solar cells during inspection, which directly affects both electrical output and the thermal patterns you can see with infrared testing. For a reliable inspection, you need enough sunlight to produce a measurable electrical signal and to create sufficient surface heating contrasts for the infrared camera. Full sun is about 1000 W/m^2, so using a level around 600 W/m^2 gives a practical lower bound—it's bright enough to yield meaningful data without requiring peak sun. A lot of inspections would struggle at much lower light (like 150 W/m^2) because signals become too weak and thermal differences too subtle to detect reliably. Higher irradiance values, such as 900 or 1200 W/m^2, would work fine but aren’t the minimum; 600 W/m^2 is the closest, sensible threshold for performing the inspection.