Q. No.Among the given options which is the minimum work function so that light from the Balmer series will not be able to cause any photo-electric effect?
| 1. | \(13.6~\text{eV}\) |
| 2. | \(\dfrac{13.6} {2}~\text{eV}\) |
| 3. | \(13.6×\left(\dfrac{3}{4}\right)~\text{eV}\) |
| 4. | \(13.6×\left(\dfrac14-\dfrac19\right)~\text{eV}\) |
Subtopic: Spectral Series |
Level 4: Below 35%
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Given below are two statements:
| 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). |
Subtopic: Spectral Series |
65%
Level 2: 60%+
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In stimulated emission, an incoming photon interacts with an excited atom (e.g. \(\mathrm{H}^{*}\)) and brings the atom to its ground state, while an extra photon is emitted - as it happens in a laser. When a photon stimulates the emission of another photon, the two photons have:
| 1. | the same phase. |
| 2. | the same energy. |
| 3. | the same direction. |
| 4. | the same phase, energy, and direction. |
Subtopic: Spectral Series |
52%
Level 3: 35%-60%
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Whenever a photon is emitted by a hydrogen atom in the Paschen series, it is followed by further emissions of photons, in the Balmer series or the Lyman series.
These photons can have:
These photons can have:
| 1. | 2 possible energy values. |
| 2. | 3 possible energy values. |
| 3. | 4 possible energy values. |
| 4. | 5 possible energy values. |
Subtopic: Spectral Series |
65%
Level 2: 60%+
Hints
In a sample of hydrogen atoms, one atom goes through a transition \(n=3\rightarrow\) ground state with emitted wavelength \(\lambda_1\). Another atom goes through a transition \(n=2\rightarrow\) ground state with emitted wavelength \(\lambda_2\). The ratio of \(\dfrac{\lambda_1}{\lambda_2}=\)
| 1. | \(\dfrac{6}{5}\) | 2. | \(\dfrac{5}{6}\) |
| 3. | \(\dfrac{27}{32}\) | 4. | \(\dfrac{32}{27}\) |
Subtopic: Spectral Series |
81%
Level 1: 80%+
JEE
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Light having the wavelength equal to the first line of the Lyman series is incident on a metal having a work function of \(6\) eV. The energy of the fastest photo-electron emitted is:
| 1. | \(7.6\) eV | 2. | \(4.2\) eV |
| 3. | \(2.1\) eV | 4. | \(0.8\) eV |
Subtopic: Spectral Series |
65%
Level 2: 60%+
Hints
The ground state energy of an electron in an \(\mathrm{H}\)-atom is \(-13.6~\text{eV}.\) If two photons, each of energy \(8~\text{eV},\) were incident on an \(\mathrm{H}\)-atom in the ground state, then the electron will:
| 1. | be emitted with excess kinetic energy |
| 2. | be excited to a higher state, but not emitted |
| 3. | be excited to a higher state and then return to the ground state |
| 4. | remain in the ground state |
Subtopic: Spectral Series |
51%
Level 3: 35%-60%
Hints
Given below are two statements:
| Assertion (A): | The energy of the photon causing the \(n=2\rightarrow4\) transition in the \(\mathrm{He}^+\text-\)ion is equal to the one causing the \(n=1\rightarrow2\) transition in the \(\mathrm{H}\text-\)atom. |
| Reason (R): | The energy level corresponding to the \(n^{\text{th}}\) quantum number of the \(\mathrm{H}\text-\)atom has the same value as the \(2n^{\text{th}}\) level of the \(\mathrm{He}^{+}\text-\)ion. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
Subtopic: Spectral Series |
65%
Level 2: 60%+
Hints
For very large \(n,\) the energy of the emitted photon, when an \(\mathrm{H}\)-atom makes a transition from energy state \(n\) to \((n-1),\) is nearly:
| 1. | \(\dfrac{13.6}{n^4}\) eV | 2. | \(\dfrac{6.8}{n^3}\) eV |
| 3. | \(\dfrac{27.2}{n^3}\) eV | 4. | \(\dfrac{54.4}{n^2}\) eV |
Subtopic: Spectral Series |
Level 3: 35%-60%
Hints
Light corresponding to the \(1^{\text{st}}\) line of Balmer series of lines (in the atomic spectrum of hydrogen) is incident onto \(\mathrm{He}^{+}\) ions in a certain excited state corresponding to (principal) quantum number \(n.\) It causes transitions due to its absorption by the \(\mathrm{He}^{+}\) ions. The value of \(n\) equals:
1. \(1\)
2. \(2\)
3. \(4\)
4. \(6\)
1. \(1\)
2. \(2\)
3. \(4\)
4. \(6\)
Subtopic: Spectral Series |
74%
Level 2: 60%+
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