In $_{88}R{a^{226}}$ nucleus, there are
$138$ protons and $88$ neutrons
$138$ neutrons and $88$ protons
$226$ protons and $88$ electrons
$226$ neutrons and $138$ electrons
In the nucleus of ${ }_{11} N a^{23}$, the number of protons, neutrons and electrons are
The neutron was discovered by
A nucleus of mass number $189$ splits into two nuclei having mass number $125$ and $64$ . The ratio of radius of two daughter nuclei respectively is:
Specify the mass of proton in kilogram and in the $'u'$ unit.
A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3: 2$. The ratio of their nuclear sizes will be $\left(\frac{x}{3}\right)^{\frac{1}{3}}$. The value of ' $x$ ' is :