Q. No.What happens when an electron makes a transition from an excited state to the ground state of a hydrogen-like atom or ion?
1.
Its kinetic energy increases but potential energy and total energy decrease.
2.
Kinetic energy, potential energy and total energy decrease.
3.
Kinetic energy decreases, potential energy increases but the total energy remains the same.
4.
Kinetic energy and total energy decrease but potential energy increases.
1. \(1\)
2. \(4\)
3. \(0.5\)
4. \(2\)
The wavelength of the first line of the Lyman series for a hydrogen atom is equal to that of the second line of the Balmer series for a hydrogen-like ion. What is the atomic number \(Z\) of hydrogen-like ions?
1. \(4\)
2. \(1\)
3. \(2\)
4. \(3\)
The ionisation potential of the hydrogen atom is \(13.6~\text{eV}.\) The hydrogen atoms in the ground state are excited by monochromatic radiation of photon energy of \(12.1~\text{eV}.\) According to Bohr’s theory, the spectral lines emitted by hydrogen atoms will be:
1. two
2. three
3. four
4. one
1. \(\frac{1}{\sqrt{m}}\)
2. \(\frac{1}{m^2}\)
3. \(m\)
4. \(\frac{1}{m}\)
The de-Broglie wavelength of an electron in the second orbit of a hydrogen atom is equal to:
| 1. | The perimeter of the orbit. |
| 2. | The half of the perimeter of the orbit. |
| 3. | The half of the diameter of the orbit. |
| 4. | The diameter of the orbit. |
| 1. | \(145\) | 2. | \(160\) |
| 3. | \(172\) | 4. | \(157\) |
(\(m_e\) represents mass of electron)
| 1. | \(0.53 \times 10^{-13} ~\text{m},-3.6 ~\text{eV}\) |
| 2. | \(25.6 \times 10^{-13} ~\text{m},-2.8 ~\text{eV}\) |
| 3. | \(2.56 \times 10^{-13} ~\text{m},-2.8 ~\text{keV}\) |
| 4. | \(2.56 \times 10^{-13} ~\text{m},-13.6 ~\text{eV}\) |
| 1. |  |
2. |  |
| 3. |  |
4. |  |
Which other physical quantity, like angular momentum, is quantized in Bohr's model of a hydrogen atom?
1. Kinetic energy
2. Magnetic moment
3. Potential energy
4. Mechanical energy
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