Q. No.
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. | \(80~\text{nm}\) |
The speed of the electron in a hydrogen atom in the \({n=1}\) level is:
1. \(1.1 \times10^{6} ~\text{m/s}\)
2. \(2.18 \times10^{6} ~\text{m/s}\)
3. \(1.08\times10^{6} ~\text{m/s}\)
4. \(3.07 \times10^{6} ~\text{m/s}\)
In accordance with Bohr’s model, what is the quantum number that characterizes the earth’s revolution around the sun in an orbit of radius with orbital speed ? (Mass of earth = )
1. \(1.8\times 10^{76}\)
2. \(2.3 \times10^{74} \)
3. \(1.3 \times10^{76} \)
4. \(2.6 \times10^{74} \)
The total energy of an electron in the first excited state of the hydrogen atom is about \(-3.4\) eV. What is the kinetic energy of the electron in this state?
1. \(3.4\) eV
2. \(-3.4\) eV
3. \(3.2\) eV
4. \(-3.2\) eV
The total energy of an electron in the first excited state of the hydrogen atom is about -3.4 eV. What is the potential energy of the electron in this state?
1. 6.8 eV
2. -6.8 eV
3. 0
4. 3.4 eV
© 2025 GoodEd Technologies Pvt. Ltd.