Selina Concise Physics Class 10 ICSE Solutions Radioactivity Selina ICSE Solutions for Class 10 Physics Chapter 12 Radioactivity Exercise 12(A) Solution 1. Three constituent of an atom are: Electrons: mass is 9.1 x 10-31 kg, charge is -1.6 x 10-19C Neutron: mass is 1.6749 x 10-27 kg, charge is zero. Protons: mass is 1.6726 x 10-27 kg, charge is +1.6 x 10-19 C Solution 2 . Atomic number – the number of protons in the nucleus is called atomic number. Mass number – the total number of nucleons in the nucleus is called mass number. Solution 3. 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 ZXA where X is the chemical symbol for the element. Solution 4....
Comments
Post a Comment