A nucleus of lead $Pb _{82}^{214}$ emits two electrons followed by an $\alpha$-particle. The resulting nucleus will have
$82$ protons and $128$ neutrons
$80$ protons and $130$ neutrons
$82$ protons and $130$ neutrons
$78$ protons and $134$ neutrons
A radioactive element $X$ emits six $\alpha$-particles and four $\beta$-particles leading to ond product ${ }_{82}^{208} Pb$. $X$ is
An atom of mass number $15$ and atomic number $7$ captures an $\alpha - $ particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be
In pair annihilation, an electron and a positron destroy each other to produce gamma radiation. How is the momentum conserved ?
On the bombardment of neutron with Boron. $\alpha$-particle is emitted and product nuclei formed is
A nuclear reaction is given by
${}_Z{X^A} \to {}_{Z + 1}{Y^A} + {}_{ - 1}{e^0} + \bar v$ , represents