I cant understand completely the concept of strong nuclear force and weak nuclear force,,,
To steal a quotation from P. A. M. Dirac, "That is a statement, not a question." :D
More seriously, you must have read something about the strong and weak forces. What, specifically, are you having trouble with? We're not mind-readers here, and I, for one, don't like to shoot blindly in the dark by trying to guess.
Strong nuclear force holds quarks together to form protons and neutrons, residue holds protons and neutrons to form nuclei.
Weak force is associated with beta decay of a nuclide.
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