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. \(4\)
2. \(1\)
3. \(2\)
4. \(3\)
The energy of a hydrogen atom in the ground state is \(-13.6\) eV. The energy of a \(\mathrm{He}^{+}\) ion in the first excited state will be:
1. \(-13.6\) eV
2. \(-27.2\) eV
3. \(-54.4\) eV
4. \(-6.8\) eV
| 1. | \(\frac{1}{Ze} \) | 2. | \(v^2 \) |
| 3. | \(\frac{1}{m} \) | 4. | \(\frac{1}{v^4}\) |
| 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 \(M_1\). |
| 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. 3.4 eV
2. 6.8 eV
3. 10.2 eV
4. zero
1. \(6.0\) Fermi
2. \(9.6\) Fermi
3. \(12.0\) Fermi
4. \(4.8\) Fermi
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
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