Non-ionising radiation is found at the long wavelength end of the spectrum and may have enough energy to excite molecules and atoms causing then to vibrate faster. This is very obvious in a microwave oven where the radiation causes water molecules to vibrate faster creating heat.
Non ionising radiation ranges from extremely low frequency radiation, shown on the far left through the radiofrequency, microwave, and visible portions of the spectrum into the ultraviolet range.
Extremely low-frequency radiation has very long wavelengths (in the order of a thousand kilometres or more) and frequencies in the range of 100 hertz or less. Radiofrequencies have wavelengths of between 1 and 100 metres and frequencies in the range of 1 million to 100 million hertz. Microwaves that we use to heat food have wavelengths that are about 1 hundredth of a metre long and have frequencies of about 10 billion hertz.
