Color and Mood. ENERGY STAR certified bulbs are available in a wide variety of shades of white light, ranging from yellowish, to white, to bluish white light, which allows you to customize the mood of your space.
The eye detects visible light, the nerves detect infrared or heat and the skin is sensitive to ultraviolet ( tanning and sunburn ) and the lens of the eye develops cataracts in response to UV also. a human body can detect ionizing electromagnetic radiation, if he can see what his geiger counter is reading.
Usually this radiation isn't visible to the human eye because it radiates at infrared wavelengths, but it can be detected by electronic devices designed for such a purpose. The term passive in this instance refers to the fact that PIR devices do not generate or radiate any energy for detection purposes.