The fundamental particles present in the nucleus of an atom are

Proton was discovered by

The nucleus and an atom can be assumed to be spherical. The radius of the nucleus of mass number $A$ is given by $R_n = 1.25 \times 10^{-13} \times A^{1/3} \, \text{cm}$. The atomic radius is $1 \, \mathring{A}$. If the mass number is $64$,the fraction of the atomic volume that is occupied by the nucleus is:

The neutron possesses:

Which of the following statements regarding cathode rays is incorrect?

Who determined the charge-to-mass ratio $(e/m_e)$ of an electron and how? Explain.