Q. No.An electron of a stationary hydrogen atom passes from the fifth energy level to the ground level. The velocity that the atom acquired as a result of photon emission will be:
(\(m\) is the mass of hydrogen atom, \(R\) is Rydberg constant and \(h\) is Plank’s constant)
1. \(\frac{24m}{25hR}\)
2. \(\frac{25hR}{24m}\)
3. \(\frac{25m}{24hR}\)
4. \(\frac{24hR}{25m}\)
(\(m\) is the mass of hydrogen atom, \(R\) is Rydberg constant and \(h\) is Plank’s constant)
1. \(\frac{24m}{25hR}\)
2. \(\frac{25hR}{24m}\)
3. \(\frac{25m}{24hR}\)
4. \(\frac{24hR}{25m}\)
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. \(4\)
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
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