A doubt regarding Cathode Ray tube

JEE Advanced Papers › Class VII-X Physics questions › A doubt regarding Cathode Ray tube

Please explain-
i) How do the electrons get accelearted in a hot Cathode Ray Tube?
ii) What is the utility of the "control grid" in the Cathode Ray Tube?

#Physics #Class VII-X Physics

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2 Answers

sengupta ·2010-07-22 03:21:56

In cathode ray tube it moves between positive and negative electrodes. It experiences attractive force towards positive and hence the acceleration.

Cotrol grid is used to control the no. of electrons reaching the anode. In this way we can control the no. of electrons reaching the screen which in turn changes the brightness.

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Ankit Maity ·2013-04-11 09:54:40

I think that you are not talking about "Cathode Ray Tube". But cathode rays in vacuum tubes. If that's the case - here's the first answer:
<<1>> Cathode rays are streams of electrons observed in vacuum tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, the glass opposite of the negative electrode is observed to glow, due to electrons emitted from and travelling perpendicular to the cathode (the electrode connected to the negative terminal of the voltage supply).
We know the principal of electrostatic induction, right.