KCET 2019 Physics Solved Paper

(D)
90Th232 → 82Pb208
Mass number changes by 24 and hence 6 α particles are emitted (as 1 α particle emitted decreased mass number by 4) then proton number should decrease by 12, but change in proton number is by 8 and hence 4 β particleshould be emitted so that proton number increased by 4