Identify the particle $x$ in the following reaction: ${}_3^7Li(p, x){}_4Be^8$,where $p$ is a proton.

The rate of disintegration of a radioactive sample can be increased by:

$A$ radioactive substance emits

$A$ $^{238}U$ nucleus decays by emitting an $\alpha$ particle of speed $v \ m/s$. The recoil velocity of the residual nucleus is (in $m/s$):

Give a brief explanation about radioactivity.

$A$ 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 $MeV$.