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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
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.
Represent the change in the nucleus of a radioactive element when a β particle is emitted.
What is meant by radioactivity?
State the penetrating range of α, β and γ radiations.
In following fig. shows a mixed source S of alpha and beta particles in a thick lead container. The particles pass through a magnetic field in a direction perpendicular to the plane of paper (inwards as shown by x). State and show in the diagram how the particles get affected.
Are all the radiations viz. α, β and γ emitted in a single radioactive decay?
What is the value of the speed of gamma radiations in air or vacuum?
The half-life of a radioactive nuclide is 100 hours. The fraction of original activity that will remain after 150 hours would be ______.
In U238 ore containing Uranium the ratio of U234 to Pb206 nuclei is 3. Assuming that all the lead present in the ore is final stable product of U238. Half life of U238 to be 4.5 × 109 years and the age of ore is ______ × 109 years. (in 109 years)
Assertion (A): Hydrogen atom consists of only one electron but its emission spectrum has may lines.
Reason (R): Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.
