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2. They also obey the laws of reflection and refraction. 3. They can also undergo interference and can be polarised. 4. When allowed to fall on metals, they cause the emission of
photoelectrons.
They can affect a photographic plate. 6. Ultra-violet rays can cause flourescence in certain materials
(Tube Lights) 7. Ultra-violet rays can not pass through glass but quartz, flourite
and rock salt are transparent to them. 8. Ultra-violet rays possess the property of synthesizing vitamin D,
when the skin is exposed to the sunlight.” 59. Ibid., p. 740
“X-Rays The discovery of X-rays was accidentally made by a German professor Rontgen in 1895. In laboratory, X-rays can be produced by using Coolidge X-ray tube. Properties. X-rays have the following properties: 1. X-rays are electromagnetic waves of very short wavelength
ranging from 0.01 A to 104. 2. X-rays travel in vacuum with the speed of light (3x108 ms-,
as they are also electromagnetic waves. 3. They are not deviated by electric and magnetic fields. 4. They affect the photographic plate very intensely. 5. They ionise the gas through which they pass. 6. They cause fluorescence in substances like zinc sulphide, barium
platinocyanide, calcium tungstate, etc. 7. Like light, X-rays can also cause photoelectric effect.
They travel in straight line and while doing so, they cast the shadows of the object falling in their path. X-rays can undergo reflection, refraction, interference, diffraction and polarisation. X-rays can penetrate the materials that are opaque to visible or ultra-violet light. They can easily pass through paper, thin sheet of metals, wood, flesh, etc. but they cannot penetrate denser objects such as bones, heavy metals etc.
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