In the following nuclear reaction,identify $x$: $_{29}Cu^{64} \to _{28}Ni^{64} + x$

$A$ radioactive atom $^X_Y M$ emits two $\alpha$ particles and one $\beta$ particle successively. The number of neutrons in the nucleus of the product will be

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

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:

When a radioactive nucleus emits an $\alpha$-particle,the mass of the atom

If it is assumed that ${}_{92}^{235}U$ decays only by emitting $\alpha$ and $\beta$ particles, the possible product of the decay is: