cathode rays

(noun)

Streams of electrons observed in vacuum tubes

Related Terms

Examples of cathode rays in the following topics:

  • Cathode Rays

    • Electrons were first discovered as the constituents of cathode rays.
    • Cathode rays are so named because they are emitted by the negative electrode, or cathode, in a vacuum tube.
    • These were the cathode rays.
    • Eugene Goldstein named them cathode rays.
    • It was used in discovery of cathode rays.

  • Cathode Ray Tube, TV and Computer Monitors, and the Oscilloscope

    • A cathode ray tube consists of a vacuum tube that contains one or more electron guns used to excite phosphors on a screen to produce images.
    • The cathode ray tube (CRT) is a vacuum tube containing one or more electron guns (a source of directed electrons) and a fluorescent screen used to view images.
    • As a matter of safety, the face is typically made of thick lead glass so as to be highly shatter-resistant and to block most X-ray emissions, particularly if the CRT is used in a consumer product.
    • Identify the primary components of a cathode ray tube and describe the use of cathode ray tubes

  • The Discovery of the Parts of the Atom

    • In 1869, he discovered a glow emitted from the cathode that increased in size with decrease in gas pressure.
    • Thomson performed experiments demonstrating that cathode rays were unique particles, rather than waves, atoms or molecules, as was believed earlier.
    • Thomson made good estimates of both the charge $e$ and the mass $m$, finding that cathode ray particles (which he called "corpuscles") had perhaps one thousandth the mass of hydrogen, the least massive ion known.
    • He showed that their charge to mass ratio (e/m) was independent of cathode material.

  • LCDs

    • Unlike the newer cathode ray tube (CRT) and plasma displays, LCDS do not use phosphors.

  • Particle Accelerator

    • A small-scale example of this class is the cathode ray tube in an ordinary, old television set.

  • Modes of Radioactive Decay

    • Alpha particles carry a positive charge, beta particles carry a negative charge, and gamma rays are neutral.
    • Other experiments showed the similarity between classical beta radiation and cathode rays; they are both streams of electrons.
    • Likewise, gamma radiation and X-rays were found to be similar high-energy electromagnetic radiation.
    • Some decay reactions release energy in the form of electromagnetic waves called gamma rays.
    • Gamma rays can only be reduced by much more substantial mass, such as a very thick layer of lead.

  • The Physics of Bremsstrahlung

    • X-rays were first produced in the laboratory by accelerating electrons along a strong electric field (a typical potential difference of 10kV) from an anode to a cathode in vacuum.
    • When the electrons hit the thick metal cathode and stop (brake), they emit cathode rays or X-rays.

  • X-Rays

    • X-radiation (composed of x-rays) is a form of electromagnetic radiation.
    • X-rays can be generated by an x-ray tube, a vacuum tube that uses high voltage to accelerate the electrons released by a hot cathode to a high velocity.
    • These x-rays have a continuous spectrum.
    • The intensity of the x-rays increases linearly with decreasing frequency, from zero at the energy of the incident electrons, the voltage on the x-ray tube.
    • Its unique features are x-ray outputs many orders of magnitude greater than those of x-ray tubes, wide x-ray spectra, excellent collimation, and linear polarization.

  • X-Ray Spectra: Origins, Diffraction by Crystals, and Importance

    • In a previous Atom on X-rays, we have seen that there are two processes by which x-rays are produced in the anode of an x-ray tube.
    • In one process, the deceleration of electrons produces x-rays, and these x-rays are called Bremsstrahlung, or braking radiation.
    • The x-ray spectrum in is typical of what is produced by an x-ray tube, showing a broad curve of Bremsstrahlung radiation with characteristic x-ray peaks on it.
    • Thus, typical x-ray photons act like rays when they encounter macroscopic objects, like teeth, and produce sharp shadows.
    • The process is called x-ray diffraction because it involves the diffraction and interference of x-rays to produce patterns that can be analyzed for information about the structures that scattered the x-rays.

  • Voltaic Cells

    • The cathode is the electrode where reduction takes place.
    • The anode will undergo oxidation and the cathode will undergo reduction.
    • At the cathode, the metal ion in the solution will accept one or more electrons from the cathode, and the ion's oxidation state will reduce to 0.
    • This forms a solid metal that deposits on the cathode.
    • Copper readily oxidizes zinc; the anode is zinc and the cathode is copper.