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प्रश्न
What are cathode rays? Why are they called ‘cathode rays’? Name a material which exhibits fluorescence when cathode rays fall on it.
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उत्तर
Cathode rays are the stream of negatively charged particles called electrons. They are called cathode rays because they are given out from cathode in a discharge tube operating at about 10,000 V when the pressure inside the tube is about 0.01 mm of Hg. Zinc Sulphide exhibits fluorescence when cathode rays fall on it.
संबंधित प्रश्न
An element `""_ZS^A` decays to `""_85R^222` after emitting 2 α particles and 1 β particle.
Find the atomic number and atomic mass of the element S.
State the energy conversion taking place in a cathode ray tube
What is meant by radioactivity?
Define the term radioactivity.
A certain nucleus A (mass number 238 and atomic number 92) is radioactive and becomes a nucleus B (mass number 234 and atomic number 90) by the loss of one particle.
What particle was emitted?
State three safety precautions that you would take while handling the radioactive substances.
It is advised not to touch a radioactive substance by hand. Give reason.
A radioctive sample decays `7/8` times its original quantity in 15 minutes. The half-life of the sample is ______.
When an α-particle of mass m moving with velocity ν bombards on a heavy nucleus of charge Ze, its distance of closest approach from the nucleus depends on m as:
