Q. No.It is found experimentally that \(13.6~\text{eV}\) energy is required to separate a hydrogen atom into a proton and an electron. The velocity of the electron in a hydrogen atom is:
1. \(3.2\times10^6~\text{m/s}\)
2. \(2.2\times10^6~\text{m/s}\)
3. \(3.2\times10^6~\text{m/s}\)
4. \(1.2\times10^6~\text{m/s}\)
1. \(3.2\times10^6~\text{m/s}\)
2. \(2.2\times10^6~\text{m/s}\)
3. \(3.2\times10^6~\text{m/s}\)
4. \(1.2\times10^6~\text{m/s}\)
| 1. | the first line of the Lyman series. |
| 2. | the second line of the Balmer series. |
| 3. | the first line of the Paschen series. |
| 4. | the second line of the Paschen series. |
The transition from the state \(n=3\) to \(n=1\) in hydrogen-like atoms results in ultraviolet radiation. Infrared radiation will be obtained in the transition from:
1. \(3\rightarrow 2\)
2. \(4\rightarrow 2\)
3. \(4\rightarrow 3\)
4. \(2\rightarrow 1\)
The total energy of an electron in the \(n^{th}\) stationary orbit of the hydrogen atom can be obtained by:
1. \(E_n = \frac{13.6}{n^2}~\text{eV}\)
2. \(E_n = -\frac{13.6}{n^2}~\text{eV}\)
3. \(E_n = \frac{1.36}{n^2}~\text{eV}\)
4. \(E_n = -{13.6}\times{n^2}~\text{eV}\)
| Assertion (A): | When light consisting of wavelengths corresponding to the Balmer series is incident on a gas containing \(\mathrm{He}^{+}\) ions in the first three excited states - it can be absorbed by the \(\mathrm{He}^{+}\) ions. |
| Reason (R): | All the energy levels of the \(\mathrm{He}^{+}\) ions are the same as those of the \(\mathrm{H}\) atoms. |
| 1. | (A) is True but (R) is False. |
| 2. | (A) is False but (R) is True. |
| 3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
1. \(1:3\)
2. \(1:30\)
3. \(7:50\)
4. \(7:108\)
| 1. | \(-3.4~\text{eV}\) | 2. | \(-6.8~\text{eV}\) |
| 3. | \(-10.2~\text{eV}\) | 4. | \(-13.6~\text{eV}\) |
These photons can have:
| 1. | 2 possible energy values. |
| 2. | 3 possible energy values. |
| 3. | 4 possible energy values. |
| 4. | 5 possible energy values. |
The Bohr model for the spectra of a \(H\)-atom:
| (a) | will not apply to hydrogen in the molecular form. |
| (b) | will not be applicable as it is for a \(He\)-atom. |
| (c) | is valid only at room temperature. |
| (d) | predicts continuous as well as discrete spectral lines. |
Choose the correct option:
| 1. | (a), (b) | 2. | (c), (d) |
| 3. | (b), (c) | 4. | (a), (d) |
An ionised \(\text H\)-molecule consists of an electron and two protons. The protons are separated by a small distance of the order of angstrom. In the ground state:
| (a) | the electron would not move in circular orbits. |
| (b) | the energy would be \(2^{4}\) times that of a \(\text H\)-atom. |
| (c) | the electron's orbit would go around the protons. |
| (d) | the molecule will soon decay in a proton and a \(\text H\)-atom. |
Choose the correct option:
| 1. | (a), (b) | 2. | (a), (c) |
| 3. | (b), (c), (d) | 4. | (c), (d) |
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