Answer:
infrared radiation
Step-by-step explanation:
infrared radiation - infrared radiation is part of electromagnetic radiation which wavelength range from about 700 nano meters (nm) to 1 millimeter (mm).
Infrared radiation is invisible to naked eye, however it can be felt as heat for longer duration infrared waves. Any type of radiation — whether it is visible light or radio waves — may possibly be hazardous if extremely focused in a high-powered narrow beam