$A$ radioactive nucleus emits $4 \alpha$ particles and $7 \beta$ particles in succession. The ratio of the number of neutrons to that of protons in the final nucleus is $[A = \text{mass number}, Z = \text{atomic number}]$

In the nuclear reaction ${}_{92}^{235}U$ decaying to ${}_{91}^{231}Pa$,what are the particles emitted?

Curie is a unit of

Which of the following rays are not electromagnetic waves?

Write nuclear reaction equations for:
$(i)$ $\alpha$-decay of $^{226}_{88}Ra$
$(ii)$ $\alpha$-decay of $^{242}_{94}Pu$
$(iii)$ $\beta^-$-decay of $^{32}_{15}P$
$(iv)$ $\beta^-$-decay of $^{210}_{83}Bi$
$(v)$ $\beta^+$-decay of $^{11}_{6}C$
$(vi)$ $\beta^+$-decay of $^{97}_{43}Tc$
$(vii)$ Electron capture of $^{120}_{54}Xe$

Which of the following will have the highest penetrating power?