On November 8, 1895, Wilhelm
Conrad Rontgen (accidentally)
discovered an image cast from his
cathode ray generator, projected
far beyond he possible range of the
• Further investigation showed that the rays were generated at the
point of the contact of the cathode ray beam on the interior of the
vacuum tube, that they were not deflected by magnetic fields, and
they penetrated many kinds of matter.
• A week after his discovery, Rontgen took an X-ray
photograph of his wife’s hand which clearly revealed
her wedding ring and her bones.
Rontgen named the new form of radiation X-
radiation or in short (X standing for
• X-rays are powerful invisible rays that can pass
through various objects and that makes it possible to see
inside things, such as a person’s luggage or the human
• X-rays are any of the electromagnetic radiations that have an
extremely short wavelength of less than 100 angstroms and have
the properties of penetrating various thickness of all solids, of
producing secondary radiations by impinging on material bodies,
and of acting on photographic films and plates as light does.
• X-rays are roughly classified into two types: soft X-rays and
hard X-rays. Soft X-rays fall in the range of the EM spectrum
between (UV) light and gamma-rays. Soft X-rays have
comparatively high frequencies — about 3 × 1016 cycles per
second, or hertz, to about 1018 Hz — and relatively short
wavelengths — about 10 nanometers (nm), or 4 × 10−7 inches,
to about 100 picometers (pm), or 4 × 10−8 inches. (A
nanometer is one-billionth of a meter; a picometer is one-
trillionth of a meter.)
• Hard X-rays have frequencies of about 1018 Hz to higher
than 1020 Hz and wavelengths of about 100 pm (4 ×
10−9 inches) to about 1 pm (4 × 10−11 inches). Hard X-rays
occupy the same region of the EM spectrum as gamma-rays.
The only difference between them is their source: X-rays are
produced by accelerating electrons, while gamma-rays are
produced by atomic nuclei.
• X-rays makes our blood cells to have higher
level of hydrogen peroxide which could
cause cell damage.
• A higher risk of getting cancer from X-rays.
• The X-rays are able to change the base of the
DNA causing a mutation.