Discovery of Radioactivity - Structure Of Atom - video Dailymotion

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The discovery of cathode rays and anode rays showed that atoms are divisible into subatomic particles. This was further supported by the discovery of radioactivity by a French scientist Henri Becquerel in 1896. Radioactivity is the phenomenon of spontaneous emission of active radiations by certain elements. The substances which emit such radiations are called radioactive substances. The common radioactive substances are uranium, radium, polonium, thorium, etc.  The effect of magnetic and electric fields on these radiations was studied by placing a small sample of radioactive substance, uranium, in a cavity of a block of lead. The radioactive radiations coming out from a narrow slit were allowed to pass through a strong electric or magnetic field. The deflections of these rays were recorded on a photographic plate. The radiations were found to split into three types of rays. These were :   Alpha rays. The rays which are deflected towards the negative electrode are called alpha rays.  Beta rays. The rays which are deflected towards the positive electrode are called beta rays. Gamma rays. The rays which are not deflected at all and are therefore, neutral are called gamma rays.  Watch the video related to *STRUCTUR OF ATOM* : https://dailymotion.com/playlist/x8m8p2   By following this channel it is very useful for the development of this channel. The Dailymotion application is easy to install on any smartphone, and does not take up much memory space.

Transcript

00:00Hi, friends. Never stop learning. Never stop developing.

00:07A substance is placed into a lead block.

00:12The lead block is not completely closed.

00:15There is a hole leading out on one side.

00:19Right in front of the hole is a fluorescent sheet.

00:24Over time, a number of spots begin to glow more and more.

00:30The spots are not evenly distributed throughout the sheet, but are concentrated in a circle.

00:38Apparently, the radius of this circle corresponds to the hole in the lead block.

00:44Of course, our minds say these spots come from the lead block.

00:50Something inside the lead block comes out through the hole to the fluorescent sheet.

00:55We don't know what it is.

00:59To analyze this, place a copper plate right between the hole and the fluorescent sheet as seen on your screen.

01:08Then connect the parallel plate to a DC voltage source.

01:15An interesting phenomenon is seen.

01:18The spots are now scattered to three different sides.

01:23Some are above, right in the middle, and some are below.

01:29It seems that something has an electric charge.

01:33Something with a negative electric charge will deviate upwards,

01:37because it is attracted to the positive charge on the parallel plate.

01:41This something is known as beta rays.

01:47Alpha rays will deviate downward because they are positively charged.

01:54While gamma rays have no charge and will continue to move straight ahead.

02:02Radioactive substances can emit three rays, namely beta rays, gamma rays, and alpha rays.

02:11This phenomenon is known as radioactivity.

02:15Radioactivity is the phenomenon of spontaneous emission of active radiations by certain elements.

02:24The substances which emit such radiations are called radioactive substances.

02:31Happy learning everyone!

02:33Based more, the stars is the equivalent!

02:34Acts of 6.

02:49.

Discovery of Radioactivity - Structure Of Atom

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