The value of one microcurie $=$ $.......$ disintegrations / second

Loss of a beta particle is equivalent to:

If a radioactive isotope with atomic number $A$ and mass number $M$ emits an $\alpha$-particle,the atomic number and mass number of that new isotope will become:

Radioactivity was discovered by

An element with atomic number $84$ and mass number $218$ loses one $\alpha$-particle and two $\beta$-particles in three successive stages. The resulting element will have:

If $_{92}U^{236}$ nucleus emits one $\alpha$-particle,the remaining nucleus will have