noun, plural: radio waves
A form of electromagnetic radiation with wavelengths of 300 millimetres or longer (even up to several kilometres)
Radio wave is a form of electromagnetic radiation with rays characterized by wavelengths of 300 millimetres or longer (even up to several kilometres). Radiation of this type is used to broadcast radio and television signals, and has frequencies up to thousands of megahertz (or one gigahertz).
In electromagnetic spectrum, the radio waves are that portion of the electromagnetic spectrum beyond the microwaves, with wavelengths as high as 30 km. They are used in communications, including television. Short wave or hf (high frequency), uhf (ultrahigh frequency) and vhf (very high frequency) waves are used in citizen's band communication. One of the natural sources of radio waves is lightning. Radio waves are currently used in telecommunication and broadcasting. As to the health effects of radio wave, there are no adverse biological effects at low level exposure. Similar to microwave, radio waves do not have enough energy to cause ionization. There were also no conclusive studies that showed radio waves emitted from cellular phones, for instance, cause or promote cancer.