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Q. No.Photoelectrons emerging from a photocathode (work function: \(2.2~\text{eV}\)) are allowed to fall onto a gas containing hydrogen atoms in the ground state and the first excited state. What is the minimum energy of the photons incident on the photo-cathode that will cause the photoelectrons to transfer energy to the \(\mathrm{H\text-}\)atoms?
| 1. | \(13.6~\text{eV}+2.2~\text{eV}\) |
| 2. | \((10.2+2.2)~\text{eV}\) |
| 3. | \((3.4+2.2)~\text{eV}\) |
| 4. | \((1.89+2.2)~\text{eV}\) |
Subtopic: Photoelectric Effect: Experiment |
Level 4: Below 35%
Hints
Consider a beam of electrons (each electron with energy \(E_0\)) incident on a metal surface kept in an evacuated chamber. Then:
| 1. | no electrons will be emitted as only photons can emit electrons. |
| 2. | electrons can be emitted but all with energy, \(E_0.\) |
| 3. | electrons can be emitted with any energy, with a maximum of \({E}_0-\phi\) (\(\phi\) is the work function). |
| 4. | electrons can be emitted with any energy, with a maximum \(E_0.\) |
Subtopic: Electron Emission |
Level 4: Below 35%
Hints
A photon of energy \(10.2\) eV corresponds to light of wavelength \(\lambda_0\). Due to electron transition from \(n = 2 \) to \(n = 1\) in a hydrogen atom, light of wavelength \(\lambda\) is emitted. If we take into account the recoil of atom when photon is emitted then:
| 1. | \(\lambda = \lambda_0\) |
| 2. | \(\lambda < \lambda_0\) |
| 3. | \(\lambda > \lambda_0\) |
| 4. | data is not sufficient to reach a conclusion |
Subtopic: Photoelectric Effect: Experiment |
Level 3: 35%-60%
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Hints
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The ratio of wavelengths of proton and deuteron accelerated by potential \(V_{p}\) and \(V_{d}\) is \(1:\sqrt2.\) Then, the ratio of \(V_{p}\) to \(V_{d}\) will be:
1. \(1:1\)
2. \(\sqrt 2: 1\)
3. \(2:1\)
4. \(4:1\)
1. \(1:1\)
2. \(\sqrt 2: 1\)
3. \(2:1\)
4. \(4:1\)
Subtopic: De-broglie Wavelength |
Level 3: 35%-60%
JEE
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Hints
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Given below are two statements:
In the light of the above statements, choose the most appropriate answer from the options given below:
| Statement I: | The de Broglie wavelength associated with a material particle depends on its charge and nature. |
| Statement II: | The wave nature of particles in sub-atomic domain is significant and measurable. |
| 1. | Both Statement I and Statement II are correct. |
| 2. | Both Statement I and Statement II are incorrect. |
| 3. | Statement I is correct but Statement II is incorrect. |
| 4. | Statement I is incorrect but Statement II is correct. |
Subtopic: De-broglie Wavelength |
Level 3: 35%-60%
NEET - 2024
Hints
\(A\) and \(B\) are two metals with threshold frequencies \(1.8\times 10^{14}\ \) Hz and \(2.2\times 10^{14}\ \) Hz. Two identical photons of energy \(0.825\) eV each are incident on them. Then, photoelectrons are emitted in:
(Take \(h=6.6\times 10^{-34}\ \) J-s)
1. \(B\) only
2. \(A\) only
3. neither \(A\) nor \(B\)
4. both \(A\) and \(B\)
(Take \(h=6.6\times 10^{-34}\ \) J-s)
1. \(B\) only
2. \(A\) only
3. neither \(A\) nor \(B\)
4. both \(A\) and \(B\)
Subtopic: Photoelectric Effect: Experiment |
Level 3: 35%-60%
Please attempt this question first.
Hints
Please attempt this question first.
Photons absorbed in matter are converted to heat. A source emitting \(n\) photon/sec of frequency \(\nu\) is used to convert \(1~\text{kg}\) of ice at \(0^{\circ}\text{C}\) to water at \(0^{\circ}\text{C}.\) Then, the time \(T\) taken for the conversion:
| (a) | decreases with increasing \(n,\) with \(\nu\) fixed |
| (b) | decreases with \(n\) fixed, \(\nu\) increasing |
| (c) | remains constant with \(n\) and \(\nu\) changing such that \(n\nu=\) constant |
| (d) | increases when the product \(n\nu\) increases |
Choose the correct option:
| 1. | (b), (d) | 2. | (a), (c), (d) |
| 3. | (a), (d) | 4. | (a), (b), (c) |
Subtopic: Particle Nature of Light |
Level 3: 35%-60%
Hints
The de-Broglie wavelength of a photon of energy \(E\) is \(\lambda_{ph}\) and that of an electron (non-relativistic) of the same energy \(E\) is \(\lambda_{e}.\) Then (assume \(E\text ~\)few \(e\text{V}\)):
1. \(\lambda_{ph}=\lambda_e\)
2. \(\lambda_{ph}<\lambda_e\)
3. \(\lambda_{ph}>\lambda_e\)
4. any of the above may be true
1. \(\lambda_{ph}=\lambda_e\)
2. \(\lambda_{ph}<\lambda_e\)
3. \(\lambda_{ph}>\lambda_e\)
4. any of the above may be true
Subtopic: De-broglie Wavelength |
Level 3: 35%-60%
Hints
Photons of wavelength \(\lambda\) cause the emission of photoelectrons from a metallic surface, the de-Broglie wavelength of the fastest photoelectron being \(\lambda_d\). A graph of \(\dfrac{1}{\lambda} \text { vs } \dfrac{1}{\lambda_{d}}\) is:
| 1. | a straight line passing through the origin. |
| 2. | a circle. |
| 3. | an ellipse. |
| 4. | a parabola. |
Subtopic: De-broglie Wavelength |
Level 3: 35%-60%
Hints
Select the correct option based on the statements given below:
| Statement I: | By de-Broglie's hypothesis momentum of an electron, \(p=h/ \lambda\). |
| Statement II: | The energy of an electron is given by; \(E=hc/ \lambda\). |
| 1. | Statement I is correct and Statement II is incorrect. |
| 2. | Statement I is incorrect and Statement II is correct. |
| 3. | Both Statement I and Statement II are correct. |
| 4. | Both Statement I and Statement II are incorrect. |
Subtopic: De-broglie Wavelength |
53%
Level 3: 35%-60%
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