When a radioactive substance emits an $\alpha$-particle,its position in the periodic table is lowered by

The decay constant of the end product of a radioactive series is

$A$ nucleus with mass number $220$ initially at rest emits an $\alpha$-particle. If the $Q$ value of the reaction is $5.5\, MeV$,calculate the kinetic energy of the $\alpha$-particle in $MeV$.

$A$ radioactive decay forms an isotope of the original nucleus with the emission of which of the following particles?

Which of the following will have the highest penetrating power?

In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following would be emitted in the decay process?