Curie is a unit of

The nucleus $_{90}Th^{228}$ transforms into $_{83}Bi^{212}$. How many $\alpha$-particles and $\beta$-particles are emitted during this process?

$A$ nucleus with $Z=92$ emits the following in a sequence: $\alpha, \alpha, \beta^{-}, \beta^{-}, \alpha, \alpha, \alpha, \alpha, \beta^{-}, \beta^{-}, \alpha, \beta^{+}, \beta^{+}$ and $\alpha$. The atomic number of the resulting nucleus is

The modern treatment method $P.E.T.$ is based on:

What is gamma decay? Explain with a proper example.

$A$ nucleus with mass number $220$ is initially at rest. It emits an $\alpha$-particle. If the $Q$-value of the reaction is $5.5 \, MeV$,then the kinetic energy of the $\alpha$-particle will be .......... $MeV$.