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What emits light when the current flows from the anode to the cathode?
lioght
How does the colour tv work?
Color TV works by putting sending more or less power through lights of different colors. In the old cathode ray tube (CRT) TVs, this was done with a phosphorus screen and a proton particle beam. In newer LCD and plasma TVs, each pixel is a light and is turned on or off in varying degrees of intensity.
What is the use of a control grid in cathode ray tube?
The grid in a cathode ray tube is used to control the beam current. The grid in the CRT is positioned near the cathode, and between it (the cathode) and any other elements, like those for focusing. The cathode is the (cylindrical) element that is coated with a metal that has good thermionic properties. That means that as it gets hot, electrons from within its structure reach such high thermal energies that they can actually leave and hang around outside of the metal itself. (Recall that the tube is very highly evacuated.) There is a heater inside the cathode to heat it up to set up the thermionic emission and the space charge. The grid is actually close to the cathode so it can affect this space charge. If the grid is driven negative, the negative grid will "push" on the space charge (the cloud of negative electrons) and keep it in place. (The tube is said to be cut off.) As the grid is driven positive, it will start attracting electrons. Yes, some will actually go to the grid, but the majority will, when flying away from the cathode (and becoming cathode rays) be "caught" by the high voltage on the anode. The stream of electrons, called a beam (because it's focused) will be pulled past the grid to go do their thing at the anode itself. The anode is actually the phosphor coating on the inside of the tube at the "front" where the viewer looks. Electrons smack the coating on the inside of the glass of the tube at a point where they are aimed and ionize it causing it to emit photons. The photons (light) will travel through the glass and out of the tube to the viewer's eyes. Recall that the grid is close to the cathode, and it tells the space charge what to do. If the grid is negative, the space charge huddles near the cathode and the tube is cut off. If the grid becomes a bit positive, some electrons zip out from the cathode, past the grid and on out to the anode. The more positive the grid, the more electrons are called out from the cathode to make the trip to the anode. Moving electrons are current. And the grid is controlling the amount of beam current.
What is recombination in electronics?
Process by which a conduction band electron gives up energy (in the form of heat or light) and falls into a valence band hole.
What are the characteristics of video display devices?
General CharacteristicsIn the CRT (cathode-ray tube) of a computer or video monitor an electron beam moves back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots (pixels) on the inside of the glass tube, thereby illuminating the active portions of the screen. By drawing many such lines from the top to the bottom of the screen, it creates an entire image. A color CRT uses three electron guns which activate red light-emitting, green light-emitting, and blue light-emitting phosphors.Abhishek JaiswalMCA IEM Kolkata
Why is the speed of electron beam greater than the light speed in cathode ray oscilloscope?
It isn't. Nothing travels faster than light, especially an electron. If it tried it would become infinitely heavy as it reached the speed of light. You would then need an infinite force to accelerate it further. To know more, Google on "special relativity"
What is state of matter forms when a fluorescent light bulb is turned on?
when a fluorescent light bulb is turned on, the state in it is still gaseous state. no change of state occurs by turning it on. It functions like a CRO(search cathode ray oscilloscope). one end acts as a cathode and the other as an anode. electron beam is produced by the cathode and it moves toward the anode. on thier way to anode, electrons collide with the walls of the glass. on the inside of the glass, it is coated with such a material that when electron collides with that surface, it produces a small flash of light. when millions of electrons do that, we see a bulb turned on.
What is the function of electron gun?
An electron gun is a device that emits a focused beam of electrons. It is commonly used in cathode ray tubes (CRT) in TVs and computer monitors to generate images by directing the electron beam onto a phosphor-coated screen, causing it to light up and produce images.
Was the cathode ray slower than the speed of light?
No, the cathode ray is faster than the speed of light.
Why are cathode rays similar to light?
they aren't. cathode rays are charged electrons, light is uncharged photons.
Why cathode dark space is dark?
The cathode dark space is dark because it contains very few electrons and ions, so there are not enough collisions happening to produce visible light. The low electron density in this region prevents the formation of plasma, which is necessary for light emission. As a result, the cathode dark space appears dark compared to other regions in the discharge tube.
Do light microscopes allow us to observe specimens in greater detail than electron microscopes?
No, electron microscopes provide higher resolution and magnification than light microscopes, allowing for observation of specimens in greater detail. This is due to the shorter wavelength of electrons compared to light, which results in higher magnification and resolution.
How do magnification and resolution compare between electron and light microscopes.?
Electron microscopes have higher magnification and resolution compared to light microscopes. Electron microscopes use electrons to create an image, allowing for much greater magnification and resolution due to the shorter wavelength of electrons compared to visible light used in light microscopes.
How do light microscopes differ from election microscope?
Light microscopes use visible light to illuminate specimens and magnify them, while electron microscopes use a beam of electrons for imaging. Electron microscopes have a much higher resolution and can magnify to much greater levels than light microscopes, allowing for the visualization of smaller structures in greater detail.
How do scientists detect cathode rays?
Cathode rays are found in vacuum tubes. Scientists are able to view them when they are a negative cathode because they emit a light and can glow.
Why is the beam of light called a cathode ray?
The beam of light is known as a cathode ray because historically it was produced in vacuum tubes by directing a stream of electrons from a negatively charged electrode (cathode) towards a positively charged electrode (anode), leading to the term "cathode ray." It was named so in reference to the electrode from which the electrons originated.
What experiment do Thomson do?
He hit plates with light
