μW/m²

microwatt per square meter

Intensityexact by definition

The microwatt per square metre is one millionth of a watt per square metre. It is used for weak radiofrequency exposure levels, faint optical signals and low-level acoustic intensity, where the threshold of human hearing at 1 kHz corresponds to about one picowatt per square metre. The factor of 1e-6 is exact, being an SI prefix.

1 μW/m² 0.000001 W/m²