How does an X-ray machine work?

An X-ray machine is essentially a camera instead of visible light, however, it uses X-rays to expose the film.

X-rays are like light in that they are electromagnetic waves, but they are more energetic so they can penetrate many materials to varying degrees. When the X-rays hit the film, they expose it just as light would. Since bone, fat, muscle, tumors and other masses all absorb X-rays at different levels, the image on the film lets you see different (distinct) structures inside the body because of the different levels of exposure on the film.

Radio waves

Radio waves are used for broadcasting radio and TV programmes. The transmitted information may be analogue or digital and uses a radio wave as a carrier. Very long wavelength radio waves can travel around the Earth, diffracting around the Earth’s surface.

Radio waves belong to the lower frequency part of the electromagnetic spectrum, which is called non-ionizing radiation. Here the electromagnetic energy is too low to break molecular bonds.

Ultraviolet waves

Ultraviolet (UV) light has shorter wavelengths than visible light. Scientists have divided the ultraviolet part of the spectrum into three regions: the near ultraviolet, the far ultraviolet, and the extreme ultraviolet.

Extreme UV

Our Sun emits light at all the different wavelengths in electromagnetic spectrum, but

it is ultraviolet waves that are responsible for causing our sunburns.

Ultraviolet waves are effective in killing bacteria and viruses. Hospitals use germicidal lamps that produce these waves to sterilize equipment, water and air in operating rooms.

Ultraviolet waves are used to identify materials by the glow or fluorescence under them. They are used to make black lights. May food and drug companies use germicidal lamps to disinfect various types of products, and their containers.

Gamma Rays

Low intensity gamma radiation can damage living cells and cause cancer.

High intensity gamma radiation will kill cells. It is used in a technique called radiotherapy to treat cancer by targeting the cancer cells with a beam of radiation

and then rotating the source of the beam as shown below.

The normal cells receive a lower dose of gamma radiation than the cancer cells, where all the rays meet. Radiotherapy aims to kill the cancer cells while doing as little damage as possible to healthy normal cells. Gamma radiation is used to kill micro organisms, which is called sterilising. It is used to sterilise food

Sources used

• http://www.hps.org/publicinformation/ate/faqs/radiationtypes.html