What are visible light, ultraviolet X-rays and gamma rays used in?

Visible light is used in communication using fibre optics. Optical fibres are very thin strands of glass. Pulse of light can be transferred down these fibres and these pulses can be used to carry information. Optical fibres are used to carry telephone and cable TV signals. This is especially useful because visible light has a short wavelength, so it can carry a great deal of information. Ultraviolet waves are used in energy-efficient lightbulbs. As ultraviolet waves have a short wavelength they carry more energy than visible light. And this energy of ultraviolet is absorbed by the internal surface of the bulb and converted into visible light. This requires much less energy than a normal light bulb. Ultraviolet is also used in suntanning e.g. using a tanning bed. Although ultraviolet increases the risk of skin cancer and causes the skin to age prematurely. X-rays and gamma rays are used in medical imaging e.g. X-rays can be used to detect broken bones, while gamma rays are used to detect cancers. Both X-rays and gamma rays are very penetrative; they easily pass through body tissue. Although X-rays are absorbed by bones so they can be seen in x-ray images. Both X-rays and gamma rays can also be used in medical treatments e.g. to treat cancer.