In a Rutherford scattering experiment, when a projectile of charge \(Z_1\) and mass \(M_1\) approaches a target nucleus of charge \(Z_2\) and mass \(M_2\), the distance of the closest approach is \(r_0\). The energy of the projectile is:

1.	directly proportional to \(M_1M_2\).
2.	directly proportional to \(Z_1Z_2\).
3.	inversely proportional to \(Z_1\).
4.	directly proportional to mass \(M_1\).

The total energy of an electron in the ground state of a hydrogen atom is -13.6 eV. The kinetic energy of an electron in the first excited state is:
1. 3.4 eV

2. 6.8 eV

3. 13.6 eV

4. 1.7 eV

The ionization potential of the hydrogen atom is 13.6 V. Hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy 12.1 eV. According to Bohr’s theory, the spectral lines emitted by hydrogen will be:

1. two

2. three

3. four

4. one

In a discharge tube ionization of enclosed gas is produced due to collisions between:

1. positive ions and neutral atoms/molecules

2. negative electrons and neutral atoms/molecules

3. photons and neutral atoms/molecules

4. neutral gas atoms/molecules

The radius of Germanium \((\mathrm{Ge})\) nuclide is measured to be twice the radius of \({}_{4}^{9}\mathrm{Be}.\) The number of nucleons in \(\mathrm{Ge}\) is:
1. \(73\)
2. \(74\)
3. \(75\)
4. \(72\)