A nuclear reaction is given by
${}_Z{X^A} \to {}_{Z + 1}{Y^A} + {}_{ - 1}{e^0} + \bar v$ , represents
fission
$\beta - $ decay
$\sigma - $ decay
fusion
$_{90}^{232}Th$ an isotope of thorium decays in ten stages emitting six $\alpha$-particles and four $\beta$-particles in all. The end product of the decay is
A certain stable nucleide, after absorbing a neutron, emits $\beta$-particle and the new nucleide splits spontaneously into two $\alpha$-particles. The nucleide is
Which of the following will have highest penetrating power
The correct order of ionizing capacity of $\alpha ,\;\beta $ and $\gamma - $ rays is
In a material medium, when a positron meets an electron both the particles annihilate leading to the emission of two gamma ray photons. This process forms the basis of an important diagnostic procedure called