CBSE Class 12-science Answered

The density of the nucleus is ver high ( of the order of 10¹⁷ ) while that of the atom is very small . This is due to the fact that the atom contains a lot of empty space , hence nuclear radius is considered till the point where the nuclear density becomes half.

'Metre', no doubt is the SI unit of distance, but for smaller distances like the radius of nucleus , we calculate it in fermi ( 1 fermi = 10^-15 m ) or angstrom ( 1 A^o = 10^-8 m ).

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