Laptops and computers emit non-ionizing radiation that is not dangerous to humans. Ionizing radiation, which includes X-rays, gamma rays and a part of the ultraviolet spectrum, is harmful to living organisms. Ionizing radiation carries enough energy that it is able to ionize atoms by freeing electrons from their orbit.
The electromagnetic spectrum encompasses all forms of electromagnetic radiation. The lowest frequencies of electromagnetic radiation belong to radio waves. Gamma rays are the highest of all electromagnetic frequencies and are extremely dangerous. Only extraordinarily dense material such as lead is able to slow or stop the passing of gamma rays. Low frequency radiation is characterized by long wave lengths, while higher frequencies are typified by shorter wave lengths.