CRT is the answer..
It's called a Cathode Ray Tube (CRT). Electrons are streamed from the back of the tube and excite phosphors on the front of the tube (the viewing side). The phosphors emit light producing the television image. This technology (CRT) is rapidly being replaced by LCD; LED; OLED and Plasma Televisions.
Airborne dust particles sometimes carry a positive or negative charge. They can even be neutral. T.V. sets have a very high voltage just behind the screen that attracts the electrons from the guns and helps make the picture. That voltage attracts dust. Run the back of your hand across the front of the screen just after you turn it off and see.
The car is running into the rain as it falls.
black since the object is blue, it reflects only blue light thus, shining red and green lights on it will only cause the object to absorb the two colors and it will result to the appearance of the object as black
A cathode ray tube (CRT) emits light when electrons strike the front of the glass tube that is covered in a phosphor coating. The front of the tube is the anode of the tube. The electrons are fired from the rear of the tube by an electrode called the cathode. The electrons are formed into a beam or ray, hence the name of cathode ray tube. Although the electrons travel from the rear of the tube to the front, or from the cathode to the anode, conventional current actually flows the opposite direction. So, the current, as measured in amps will flow from the anode to the cathode.
Cathode Ray TubeLight is produced when electrons emitted from the back of the tube strike the front of the screen,and light up the phosphor coating .PlasmaExcitation of a gas by high voltageLCDCold cathode florescent lamps, placed behind the LCD screenLCD LEDWhite LED's placed behind the LCD screenOLEDLight emitting diodes. Light is generated by passing current across a PN junction of specially doped material, which causes electrons to change valence level and emit light.
It works on the following principles : (i)thermionic emission (ii)deflection of the electron beam by the electric and magnetic field (iii)fluorescence produced by the electron beam on a fluorescent screen
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.
CRO consists of a cathode ray tube which is having the vacuum conditions . The electron beam is emitted by a cathode at the rear end of the tube. This beam is accelerated and focused by one or more anodes. The rays then strike the front (other end) of the tube and produces a bright spot on the phosphorescent screen
Electrons striking the phosphors at the front of the picture tube are what generate the photons our eyes see. Electrons (negatively charged) don't move unless forced to by either an electric field or a magnetic field - in this case an electric field - created by the circuitry in the TV. The distance from the back of the picture tube neck where electrons are generated (the cathode, negative charge, repels electrons) to the front of the screen where they are needed is large, perhaps 20 or 30 or more inches. Though the picture tube is evacuated, it is not a perfect vacuum and many atoms still exist inside it, which results in resistance to electron flow. Ohm's Law - Voltage = Current x Resistance - determines what happens electrically. Since the resistance of the atoms inside the tube is quite high to electrons, a high voltage is required to overcome it and force the electrons to move and strike the screen in sufficient quantity (current), after which they fall back to the metal coating inside the picture tube (the anode, positive charge, attracts electrons), completing the circuit that started at the cathode. A lower voltage will simply not provide enough force to do the job.
On the front screen On the front screen
If you have read How Television Works or watched What If I Shot My TV?, then you have heard about electron guns. They sound a little bit like something out of "Star Wars," but they're actually the devices that are the heart of most TVs and computer monitors.The idea behind an electron gun is to create electrons and then accelerate them to a very high speed. In a cathode ray tube (CRT) -- the big glass tube used in most televisions and computer monitors -- the electrons get aimed at the screen, where they light up the phosphor on the screen to create the image.The electron gun from a CRT computer monitor is about the size of a roll of quarters. It contains the heater, cathode, focusing anode and accelerating anode for three electron beams.The electron gun starts with a small heater, which is a lot like the hot, bright filament of a regular light bulb. It heats a cathode, which emits a cloud of electrons. Two anodes turn the cloud into an electron beam:The accelerating anode attracts the electrons and accelerates them toward the screen.The focusing anode turns the stream of electrons into a very fine beam.When the electrons leave the accelerating anode, they are traveling at a reasonable fraction of the speed of light, and this gives them a lot of energy. When they hit the phosphor coating on the back of the front glass, the phosphor converts the electron beam's energy to photons and lights up.A black-and-white TV has a single electron gun, while a color TV needs three guns because each pixel on the screen is made of a red, a green and a blue dot.
In front of a screen
The previous generation of televisions were known as CRT televisions. CRT stands for cathode ray tube. The tube sent a stream of electrons from the back of the tube to the front phosphor coated glass face. The electrons caused the phosphors to glow according to the intensity of the electron beam.
Flat screens are the easiest to view from a wide range of angles and accurately reproduce the original film or video recording. Older CRT televisions had curved screens because of the design of the electron guns inside that fired electrons to the front of the screen in an arc.