CATHODE RAY TUBE.

The cathode ray tube (CRT) is a vacuumtube containing one or more electron guns(a source of electrons or electron emitter)and a fluorescent screen used to viewimages. It has a means to accelerate anddeflect the electron beam(s) onto thescreen to create the images. The images may represent electricalwaveforms (oscilloscope), pictures(television, computer monitor), radartargets or others. CRTs have also been used as memorydevices, in which case the visible lightemitted from the fluorescent material (ifany) is not intended to have significantmeaning to a visual observer (though thevisible pattern on the tube face maycryptically represent the stored data).

Cathode:The cathode is the negativelycharged electrode.The cathode attracts cations orpositive charge.The cathode is the source ofelectrons or an electron donor. It mayaccept positive charge.

Anode:The anode is the positively chargedelectrode.The anode attracts electrons oranions.The anode may be a source ofpositive charge or an electronacceptor.

THOMSON’S EXPERIMENT WITH CATHODE RAY DISCHARGE TUBE

Experiments on the magnetic deflection of cathode rays:Thomson first investigated the

magnetic deflection of cathode rays.Cathode rays were produced in theside tube on the left of the apparatusand passed through the anode into themain bell-jar, where they weredeflected by a magnet.Thomson detected their path by the

fluorescence on a squared screen inthe jar.He found that whatever the material

of the anode and the gas in the jar,the deflection of the rays was thesame, suggesting that the rays wereof the same form whatever theirorigin.

THOMSON’S EXPERIMENT WITH CATHODE RAY DISCHARGE TUBE

Thomson constructed a Crookes tube with a near-perfect vacuum. At the start of the tube was the cathode from which the rays projected. The rays were sharpened to a beam by two metal slits – the first of these slits doubled as the anode, the second was connected to the earth. The beam then passed between two parallel

aluminum plates, which produced an electric field between them when they were connected to a battery. The end of the tube was a large sphere where the beam would impact on the glass, created a glowing patch. Thomson pasted a scale to the surface of this sphere to measure the deflection of the beam.When the upper plate was connected to the

negative pole of the battery and the lower plate to the positive pole, the glowing patch moved downwards, and when the polarity was reversed, the patch moved upwards.

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DONE BY:RAHUL SRIVATSAN.M.R.VISHWANATH.A.DHANRAJ.D.SANJAY.S.GANAPATHY.M.ABHINAV.R.SANTHOSH.S.VIVEK.S.VARUN PRASATH.B.AKASH.L.K.

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