Q. No.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. \(2.5\times10^{15}~\text{Hz}\)
1. \(4\times10^{15}~\text{Hz}\)
2. \(5\times10^{15}~\text{Hz}\)
3. \(1.6\times10^{15}~\text{Hz}\)
4. \(2.5\times10^{15}~\text{Hz}\)
| 1. | \(n= 3~\text{to}~n=2~\text{states}\) |
| 2. | \(n= 3~\text{to}~n=1~\text{states}\) |
| 3. | \(n= 2~\text{to}~n=1~\text{states}\) |
| 4. | \(n= 4~\text{to}~n=3~\text{states}\) |
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 \((\mathrm{Ge})\) 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. \(72\)
| 1. | \(3.4~\text{eV},~3.4~\text{eV}\) |
| 2. | \(-3.4~\text{eV},~-3.4~\text{eV}\) |
| 3. | \(-3.4~\text{eV},~-6.8~\text{eV}\) |
| 4. | \(3.4~\text{eV},~-6.8~\text{eV}\) |
| 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. |
| 1. | \(\frac{3}{23}\) | 2. | \(\frac{7}{29}\) |
| 3. | \(\frac{9}{31}\) | 4. | \(\frac{5}{27}\) |
1. \(\frac{1}{\sqrt{m}}\)
2. \(\frac{1}{m^{2}}\)
3. \(m\)
4. \( \frac{1}{m}\)
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. \(1:-2\)
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