The diagram of the electromagnetic spectrum in figure 6-18, shows various properties across the range of frequencies and wavelength. Electromagnetic spectrum the figures at the bottom of the diagram represents the approximate scale of wavelengths. It starts from the smallest to the largest. Which is the Atomic nucleus, atom, virus, bacteria, pinhead, fingernail, humans, skyscrapers, and mount Everest. The figure also shows the wavelength and the frequency scale. The region of the spectrum are broadly classified into the following classes radio, microwave, infrared, ultraviolet, X-rays, and gamma rays. The term “radiation” means the emission of energy as electromagnetic waves or as moving subatomic particles. Gamma rays: used in cancer radiation treatments, come from radioactive material, also from supernova explosions. X-rays used in airports to look inside luggage, used for medical diagnostics, also created in stars (like our sun).Ultraviolet used to sterilize medical equipment and some foods, emitted by the sun and can cause skin cancer and mutations in plants. Infrared an oven, a stovetop, a curling iron, and a blow-dryer use infrared (heat), so does a heat lamp at a buffet table to keep hot foods hot, we feel it as the heat of the sun. Microwave used by microwave ovens (hence the name) to cook food, used for communications, radar, plasma physics, and is a branch of astronomy that studies microwaves (most notably the study of the cosmic background microwave radiation left over from the Big Bang).Radio waves used for broadcasting news and music to car radios, used for some medical treatments, Jupiter and our sun are the nearest radio sources in the sky.