Combined Defence Services Exam, CDS I 2020 General Knowledge Paper Solved: 1. Scattering of α-particles by a thin gold foil suggests the presence ofA. Electron in an atomB. Proton in an atomC. Positively charged nucleus at the centre of an atomD. Isotopes of gold Ans: Positively charged nucleus at the centre of an atom (C) Ans: (d) 3. Which one of the following chemical reactions is not feasible?A. Fe + CuSO4→ FeSO4 + CuB. Zn + CuSO4→ ZnSO4 + CuC. Cu + PbCl2→ CuCl2 + PbD. Mg + CuSO4→ MgSO4 + Cu Ans: Cu + PbCl2→ CuCl2 + Pb (C) … Continue reading CDS I 2020 General Knowledge Paper Solved