![]() ![]() If no deflecting electrons travel in a straight line from the hole in the accelerating the screen, where they produce a bright spot. To analyze the electron motion, let’s first calculate the speed they leave the electron gun. The assembly of focusing anode, and accelerating electrode is called the electron The am of electrons passes between two pairs of deflecting between the first pair of plates deflects the electrons horizontally between the second pair deflects them vertically. We won’t need to grid or focusing anode in the following analysis. The focusing anode ensures that electric leaving the cathode in slightly different directions are focused d and all arrive at the same spot on the screen. The area where the electrons strike the screen glows the number of electrons that reach the anode and hence on the screen. Electrons passing through the hole in beam and travel with constant horizontal velocity from the screen. This potent an electric field directed from right to left in the region anode and the cathode. The cathode, at the left end in the figure, the heater, and electrons evaporate from the surface of, with a small hole at its center, is maintained at of the order of 1 to 20 kY, relative to the cathode. Cathode-ray tubes use an electron beam before the was understood, it was called a cathode ray because it emanated of a vacuum tube diagram of the principal elements of a cathode-ray tube. is a very good vacuum, with a pressure of around 0.01 Pa greater pressure, collisions of electrons with air molecules beam excessively. Cathode-ray tubes are found in used in TV picture tubes and computer displays. Do not proceed to schedule a custom demo unless you have already conferred with the lecture demonstrator about it.Of potential is applied to an important class of devices or “CRTs” for short. The custom demos section of the website is used by UO chemistry instructors to schedule demonstrations that are not listed in the database. The university shall not be liable for any special, direct, indirect, incidental, or consequential damages of any kind whatsoever (including, without limitation, attorney's fees) in any way due to, resulting from, or arising in connection with the use of or inability to use the web site or the content. The university further disclaims all responsibility for any loss, injury, claim, liability, or damage of any kind resulting from, arising out or or any way related to (a) any errors in or omissions from this web site and the content, including but not limited to technical inaccuracies and typographical errors, or (b) your use of this web site and the information contained in this web site.the university shall not be liable for any loss, injury, claim, liability, or damage of any kind resulting from your use of the web site. The university expressly disclaims all warranties, including the warranties of merchantability, fitness for a particular purpose and non-infringement. This web site is provided on an "as is" basis. "Do not do demos unless you are an experienced chemist!" Please read the following disclaimer carefullyīy continuing to view the descriptions of the demonstrations you have agreed to the following disclaimer. Clicker questions assess student understanding of how the cathode ray tubes led to scientists understanding of the properties of electrons. A block Power Point presentation used to facilitate the demonstrations and the class activity is available. The electron beam is deflected by an electric field and a magnetic field. Cathode Ray Tube # 18 - in a darkened room, the electron beam (cathode rays) shows up on a phosphor screen as a bright blue line. ![]() However, when cathode rays strike the pinwheel inside the CRT, the pinwheel begins to spin and move. Cathode Ray Tube #16 - light shined on a pinwheel inside a CRT does not cause the pinwheel to move. Cathode Ray Tube #12 provides evidence that cathode rays are not visible to human eyes. Cathode Ray Tube #14 - cathode rays cast a shadow behind a Maltese Cross. A series of cathode ray tubes graphically demonstrate various properties of the electron. ![]() The activity sheet has embedded questions designed to promote small group discussions. The diagrams help students understand the significance of each experiment. The activity sheet has diagrams of each of the cathode ray tubes used in the demonstration. A class activity sheet accompanies the cathode ray tube demonstrations and experiments. ![]()
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