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प्रश्न
What is nucleus of an atom? Compare its size with that of the atom. Name its constitutents. How is the number of these constituents determined by the atomic number its atomic model.
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उत्तर
The nucleus at the centre of atom, whose size is of the order of 10-15 m to 10-14 m.
The size of a nucleus is 10-5 to 10-4 times the size of an atom. It consists of protons and neutrons.
If Z is the atomic number and A is the mass number of an atom, then the atom contains Z number of electrons; Z number of protons and A - Z number of neutrons.
The atom is specified by the symbol \[\ce{^A_Z X}\] where X is the chemical symbol for the element.
संबंधित प्रश्न
What are free electrons?
What is thermionic emission?
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.
An element P disintegrates by α - -emission and the new element suffers two further disintegrations, both by β -emission, to form an element Q. Explain the fact that P and Q are the isotopes.
State three safety precautions that you would take while handling the radioactive substances.
How is a cathode ray beam affected while passing through an electric field?
Unit of radioactivity is _______
A radioactive material decays by simultaneous emissions of two particles with half-lives of 1400 years and 700 years respectively. What will be the time after which one-third of the material remains? (Take In3 = 1.1)
The activity of a certain radionuclide decreases to 15 percent of its original value in 10 days. What is its half life?
[ln (0.15) = -1.9]
