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| Cathode Rays |
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The cathode rays are stream of electrons emitted from the cathode of a discharge tube at low pressure under the influence of a very high potential difference between anode and cathode. |
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Some important properties of cathode rays are : |
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Cathode rays travel in straight lines and cast sharp shadows of the objects placed in their path.
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Cathode rays are emitted normally from the surface of the cathode. |
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Cathode rays exert mechanical force on the objects on which they fall.
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Cathode rays produce heat when they fall on matter because kinetic energy of cathode rays is converted into heat. |
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Cathode rays are deflected by atomic fields.
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Cathode rays are also deflected by magnetic field.
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Cathode rays ionize the gas through which they pass.
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They travel with high speed ranging from 1/20 to 1/10 of the velocity of light.
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Cathode rays can pass through thin sheets of matter.
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They can affect a photographic film.
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They produce fluorescence when they fall on certain substances; the color depends upon the nature of the substance. It is green for willemite and greenish blue for zinc sulphide.
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The cathode rays are independent of the nature of the gas or electrodes used in the discharge tube.
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When fast moving cathode rays are stopped by a metal of light atomic number, X-rays are produced.
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