$1$ curie represents

The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter nucleus is an

$A$ 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 $MeV$.

Explain the $\alpha$-decay process and give its appropriate example.

Neutrino is a particle which $\qquad$

$A$ nucleus of $_{84}^{210}Po$ originally at rest emits an $\alpha$ particle with speed $v$. What will be the recoil speed of the daughter nucleus?