Search results
Results From The WOW.Com Content Network
Cathode rays or electron beams (e-beam) are streams of electrons observed in discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitted from the cathode (the electrode connected to the negative terminal of the voltage ...
where Ψ(x) is the electron wave-function, expressed as a function of distance x measured from the emitter's electrical surface, [62] ħ is the reduced Planck constant, m is the electron mass, U(x) is the electron potential energy, E n is the total electron energy associated with motion in the x-direction, and M(x) = [U(x) − E n] is called ...
The cathode can be negative like when the cell is electrolytic (where electrical energy provided to the cell is being used for decomposing chemical compounds); or positive as when the cell is galvanic (where chemical reactions are used for generating electrical energy). The cathode supplies electrons to the positively charged cations which flow ...
An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode-ray tubes (CRTs), used in older television sets , computer displays and oscilloscopes , before the advent of flat-panel displays .
A cathode electrode in a vacuum tube or other vacuum system is a metal surface which emits electrons into the evacuated space of the tube. Since the negatively charged electrons are attracted to the positive nuclei of the metal atoms, they normally stay inside the metal and require energy to leave it. [1]
[10] [2] As Abraham Pais described it, "Now the beauty of Franck and Hertz's work lies not only in the measurement of the energy loss E 2-E 1 of the impinging electron, but they also observed that, when the energy of that electron exceeds 4.9 eV, mercury begins to emit ultraviolet light of a definite frequency ν as defined in the above formula ...
The pressure is such that the electrons are decelerated by collisions as little as possible (change in kinetic energy), the number of collisions are few but sufficient to emit visible light. Inside the bulb there is an electron gun. This consists of a heating spiral, a cathode and an anode hole.
An electron in the phosphor absorbs a high-energy photon from the applied radiation, exciting it to a higher energy level. After losing some energy in non-radiative transitions, it eventually transitions back to its ground state energy level by fluorescence, emitting a photon of lower energy in the visible light region.