Q. No.Electron in hydrogen atom first jumps from the third excited state to the second excited state and then from the second excited to the first excited state. The ratio of the wavelengths \(\lambda_1:\lambda_2\) emitted in the two cases is:
1. \(\frac{7}{5}\)
2. \(\frac{20}{7}\)
3. \(\frac{27}{5}\)
4. \(\frac{27}{20}\)
1. \(\frac{7}{5}\)
2. \(\frac{20}{7}\)
3. \(\frac{27}{5}\)
4. \(\frac{27}{20}\)
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. \(\frac{24hR}{25m}\)
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
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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