How does x-ray works?

Answer 1

X-Rays are electromagnetic waves (most like light waves) with wavelength much smaller than visible light. Visible light has a wavelength in the range from about 380 nm to about 740 nm (one nm is one part of a meter out of one billion), while X-Rays have a wavelength range from 10 nm to 5 pm (one pm is 0.001 nm).

The photon energy E is inversely proportional to the wavelength l, since it is

E=h c / l

where h is the Plank constant and c the light speed in vacuum. Thus X-rays photons are much more energetic than visible light photons. This is the reason why X-ray photons are capable to penetrate materials much more efficiently and to break weak molecular bonds. This last X-ray capability is what causes them to be dangerous,, differently from visible light whose photons are much less energetic and do not cause weak chemical bonds breakage.

As a matter of fact, interaction of X-rays with nucleic acids in the human cells (specially with DNA) can cause modifications in this molecules that, if not corrected by the suitable biochemical mechanisms that are present in human cells, can cause genetic illnesses, mainly tumors. Fortunately this is a rare phenomenon, since human body is quite efficient in correcting wrong DNA replicas or killing the cells containing them.

X-rays have several applications, from medical imaging, where low energy X-rays are used, to airport security to X-ray lithography.

Answer 2

X-rays are a form of electromagnetic radiation that can pass through soft tissues in the body but are absorbed by denser materials like bone. When an x-ray machine is used, a beam of x-rays passes through the body and creates an image on a detector, which can then be used to create a visual representation of the internal structures.