Soft and Hard X–Rays and Properties of X–Rays | Physics4students
X–rays are of two types :
(i) Soft X–rays
X–rays having wavelength of 4 angstrom or above, have lesser frequency and hence lesser energy. They are called soft X – rays due to their low penetrating power. They are produced at comparatively low potential difference.
(ii) Hard X–rays
X–rays having low wavelength of the order of one angstrom have high frequency and hence high energy. Their penetrating power is high, therefore they are called hard X–rays. They are produced at comparatively high potential difference.
The wavelength of X–rays depends upon the kinetic energy of the electrons producing them and this kinetic energy depends upon the potential difference between the filament and the target.
Properties of X–rays
(i) X–rays are electromagnetic waves of very short wave length. They travel in straight lines with the velocity of light. They are invisible to eyes.
(ii) They undergo reflection, refraction, interference, diffraction and polarisation.
(iii) They are not deflected by electric and magnetic fields. This indicates that X-rays do not have charged particles.
(iv) They ionize the gas through which they pass.
(v) They affect photographic plates.
(vi) X–rays can penetrate through the substances which are opaque to ordinary light e.g. wood, flesh, thick paper, thin sheets of metals.
(vii) When X–rays fall on certain metals, they liberate photo electrons (Photo electric effect).
(viii) X-rays have destructive effect on living tissue. When the human body is exposed to X-rays, it causes redness of the skin, sores and serious injuries to the tissues and glands. They destroy the white corpuscles of the blood.
(ix) X–rays do not pass through heavy metals such as lead and bones. If such objects are placed in their path, they cast their shadow.
