An electron in Bohr's hydrogen atom has angular momentum . The energy of the electron is
1. -3.4 eV
2. -0.64 eV
3. -0.85 eV
4. -10.25 eV
If the energy of the electron in an \(\mathrm{H}\)-atom in the ground state is taken to be \(-13.6\) eV, then the kinetic energy of the electron in the first excited state will be:
1. \(3.4\) eV
2. \(6.8\) eV
3. \(10.2\) eV
4. \(13.6\) eV
For which one of the following Bohr models is not valid?
| 1. | Singly ionised helium atom \(\big(\mathrm{He}^{+}\big).\) |
| 2. | Deuteron atom. |
| 3. | Singly ionised neon atom \(\big(\mathrm{Ne}^{+}\big).\) |
| 4. | Hydrogen atom. |
( \(m_e\) represents the mass of an electron)
| 1. | \(0.53\times10^{-13}~\text{m}, ~-3.6~\text{eV}\) |
| 2. | \(25.6\times10^{-13}~\text{m}, ~-2.8~\text{eV}\) |
| 3. | \(2.56\times10^{-13}~\text{m}, ~-2.8~\text{keV}\) |
| 4. | \(2.56\times10^{-13}~\text{m}, ~-13.6~\text{eV}\) |
Which one of the following statements is not true?
| 1. | The sizes of the atoms taken in Thomson's model and Rutherford's model have the same order of magnitude. |
| 2. | In the ground state of Thomson's model, the electrons are in stable equilibrium. However, in Rutherford's model, the electrons always experience a net force. |
| 3. | A classical atom based on Thomson's model is doomed to collapse. |
| 4. | The positively charged part of the atom possesses most of the mass in both the models. |
What is the shortest wavelength present in the Paschen series of spectral lines?
1. \(818.9~\text{nm}\)
2. \(779~\text{nm}\)
3. \(500~\text{nm}\)
4. \(1024~\text{nm}\)
A difference of \(2.3\) eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom makes a transition from the upper level to the lower level?
1. \(6.6\times10^{14}\) Hz
2. \(5.6\times10^{14}\) Hz
3. \(9.3\times10^{14}\) Hz
4. \(7.9\times10^{14}\) Hz
The ground state energy of the hydrogen atom is \(-13.6~ \text {eV}.\) What is the potential energy of the electron in this state?
1. \(-13.6~\text{eV}\)
2. \(27.2~\text {eV}\)
3. \(-27.2~ \text {eV}\)
4. \(13.6~\text {eV}\)
The radius of the innermost electron orbit of a hydrogen atom is \(5.3\times10^{-11}\) m. What is the radius of the \(n=2\) orbit?
1. \(1.67 ~\mathring A\)
2. \(4.77~\mathring A\)
3. \(2.12~\mathring A\)
4. \(3.11~\mathring A\)
A hydrogen atom initially in the ground level absorbs a photon, which excites it to the \(n=4\) level. The wavelength of the photon is:
| 1. | \(97~\text{nm}\) | 2. | \(89~\text{nm}\) |
| 3. | \(45~\text{nm}\) | 4. | \(80~\text{nm}\) |
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