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

Radioactivity was discovered by

In the radioactive disintegration series,for the process $_{92}^{238}U \xrightarrow{\alpha} X \xrightarrow{\beta^-} {}_{Z}^{A}Y$,the values of $Z$ and $A$ respectively are:

The equation $_{Z}X^{A} \to _{Z+1}Y^{A} + _{-1}e^{0} + \bar{\nu}$ represents:

$A$ nucleus ${ }_{Z} X^{A}$ emits an $\alpha$-particle with velocity $v$. The recoil speed of the daughter nucleus is

Originally, radioactive beta decay was thought to be a decay of a nucleus with the emission of electrons only (Case $I$). However, in addition to the electron, another (nearly) massless and electrically neutral particle is also emitted (Case $II$). Based on the figure below, which of the following is correct?