The radius of an atom is of the order of

Who discovered the proton and the neutron?

Arrange the $\frac{e}{m}$ (charge-to-mass) ratio in increasing order for the following particles: $e, p, n, \alpha$.

Cathode rays have

The radius of a nucleus with mass number $A$ is given by $1.25 \times 10^{-13} \times A^{1/3} \ cm$. If the radius of the atom is $1 \ \mathring{A}$ and the mass number is $64$,calculate the fraction of the volume occupied by the nucleus.

The mass of the proton is $1840$ times that of the electron. If the potential difference applied is $V$,the kinetic energy of the proton is ............ $KeV$.