It is written for patients and gives information about taking or using a medicine. It is possible that the leaflet in your medicine pack may differ from this version because it may have been updated since your medicine was packaged. Please click on the link to the left to view the PIL in PDF format.
UV Irradiance is the radiant power, within a stated wavelength range, arriving at a surface per. unit area, usually expressed in watts or milliwatts per square centimeter. Irradiance varies with lamp. output power, efficiency and focus of its reflector system, and distance to the surface.
Relation between Radiance and Irradiance. As you stated both radiometry units seem to be similar. While irradiance refers to incoming power, the radiance is used for two cases: angle dependant diffuse reflection (BRDF) emission from light sources. E.g. radiance in direction of the optical axis of a LED is higher, than it's radiance at an angle of 15Â°. Optical simulations / ray tracing calculate the irradiance on surfaces. Your last two questions are mainly correct.