00:00The following is an illustration of the apparatus to explain one of the properties of cathode rays in this tutorial.
00:10The first component is a closed glass tube.
00:14The air inside has been pumped out.
00:17So inside the tube, there is a vacuum, or has very low air pressure.
00:23It can also be called a gas discharge tube.
00:27The metal plate on the top left is connected to the negative pole of a DC voltage source, called the cathode.
00:35The metal plate on the top right is connected to the positive pole of the DC voltage source, referred to as the anode.
00:44Inside the tube, there is a wheel made of light metal.
00:49When all electrical circuits have been connected and turned on,
00:53the wheel in the tube starts to rotate and moves translationally to the right, or towards the anode side.
01:07How could this happen?
01:12Okay, we will simplify the equipment into the following.
01:16A cathode.
01:17A pinwheel.
01:19There are two possibilities here.
01:21The first possibility is that cathode rays are ordinary electric light or electromagnetic waves.
01:28When electromagnetic waves touch the blades on the wheel, these waves will be reflected or absorbed by the blades,
01:34in accordance with the laws of reflection and refraction of light.
01:38The pinwheel won't turn or move.
01:41This is not in accordance with the observation results.
01:44So cathode rays are not electromagnetic waves.
01:47The second possibility is that cathode rays are particles that have mass.
01:52When an object with mass having a certain speed touches an object with another mass that is at rest, a collision process will occur.
02:00This causes a change in momentum on the blade.
02:03So the blade has speed towards the right.
02:06Because the center of mass of the wheel is on the axis, then the wheel will rotate while moving translationally to the right.
02:13This is in accordance with the results of observations.
02:19So cathode rays are actually the movement of particles with mass from the cathode to the anode.
02:25Later known as electrons.
02:29Thank you for watching the video on this channel.
02:33And, don't forget to watch the next video.
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