Monochromatic radiation emitted when electron on hydrogen atom jumps from first excited to the ground state irradiates a photosensitive material. The stopping potential is measured to be \(3.57~\text{V}\). The threshold frequency of the material is:
1. \(4\times10^{15}~\text{Hz}\)
2. \(5\times10^{15}~\text{Hz}\)
3. \(1.6\times10^{15}~\text{Hz}\)
4. \(2.5\times10^{15}~\text{Hz}\)
If the nucleus has a nuclear radius of about 3.6 fermis, then would have its radius approximately as:
1. 6.0 Fermi
2. 9.6 Fermi
3. 12.0 Fermi
4. 4.8 Fermi
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 (Ge) nuclide is measured to be twice the radius of . The number of nucleons in Ge is:
1. 73
2. 74
3. 75
4. 72
The total energy of an electron in the orbit of an atom is \(-3.4~\mathrm{eV}\). Its kinetic and potential energies are, respectively:
1. | \(3.4~\mathrm{eV},~3.4~\mathrm{eV}\) |
2. | \(-3.4~\mathrm{eV},~-3.4~\mathrm{eV}\) |
3. | \(-3.4~\mathrm{eV},~-6.8~\mathrm{eV}\) |
4. | \(3.4~\mathrm{eV},~-6.8~\mathrm{eV}\) |
\(\alpha\text{-}\)particle consists of:
1. | \(2\) protons only |
2. | \(2\) protons and \(2\) neutrons only |
3. | \(2\) electrons, \(2\) protons, and \(2\) neutrons |
4. | \(2\) electrons and \(4\) protons only |
The ratio of the longest wavelengths corresponding to the Lyman and Balmer series in the hydrogen spectrum is:
1. | \(\frac{3}{23}\) | 2. | \(\frac{7}{29}\) |
3. | \(\frac{9}{31}\) | 4. | \(\frac{5}{27}\) |
The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom is:
1. \(1:1\)
2. \(1:-1\)
3. \(2:-1\)
4. \(1:-2\)