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प्रश्न
In a cathode ray tube state the purpose of the fluorescent screen.
उत्तर
Fluorescent screen helps to obtain images on the screen by converting electrical signals to light (or) visual signals by ionizing radiations to light waves.
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संबंधित प्रश्न
In a cathode ray tube state:
(i) the purpose of covering cathode by thorium and carbon.
(ii) the purpose of the fluorescent screen.
(iii) how is it possible to increase the rate of emission of electrons.
Give a scientific explanation.
When the radiation coming out from a certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path.
Give the relative ionizing power of α, β and γ radiations.
In the following fig. shows a radioactive source S in a thick lead container. The radiations pass through an electric field between the plates P and Q. Complete the diagram to show the paths of α , β and γ radiations.
Why is the source S placed in a thick lead container?
Name two radioactive substances.
State two properties that a substance should possess when used as a thermionic emitter.
What are cathode rays? Why are they called ‘cathode rays’? Name a material which exhibits fluorescence when cathode rays fall on it.
State one use of radio-isotopes.
Unit of radioactivity is _______
