In a radioactive decay process,the atomic number and mass number of the nucleus do not change. Which of the following is emitted during this process?

$A$ radioactive reaction is $_{92}U^{238} \to _{82}Pb^{206}$. How many $\alpha$ and $\beta$ particles are emitted?

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

The $Q$-value of the decay ${ }_{11}^{22} Na \rightarrow{ }_{10}^{22} Ne + e ^{+}+v$ is

$A$ radioactive element ${}_{92}^{242}X$ emits two $\alpha$-particles,one electron,and two positrons. The product nucleus is represented by ${}_{P}^{234}Y$. The value of $P$ is $..................$

Which ray contains positively charged particles?