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Q. No.The graph between the kinetic energy \((E_k)\) and the de-Broglie wavelength \((\lambda)\) of a moving electron is best represented by:
1.
2.
3.
4.
Subtopic: De-broglie Wavelength |
57%
Level 3: 35%-60%
Hints
The de-Broglie wavelength of light (i.e. photons) of frequency \(f\) (calculated using de-Broglie relation):
| 1. | is directly proportional to \(f\) |
| 2. | is inversely proportional to \(f\) |
| 3. | is inversely proportional to \(\sqrt f\) |
| 4. | does not exist |
Subtopic: De-broglie Wavelength |
61%
Level 2: 60%+
Hints
When the frequency of incident radiation (causing photoelectric effect) is increased, the de-Broglie wavelength of the:
| 1. | fastest photoelectron increases |
| 2. | slowest photoelectron decreases |
| 3. | fastest photoelectron decreases |
| 4. | slowest photoelectron increases |
Subtopic: De-broglie Wavelength |
68%
Level 2: 60%+
Hints
Two metals \(A\) and \(B,\) when exposed to light of wavelength \(400~\text{nm}\) shows the photoelectric effect. However, when light of wavelength \(620~\text{nm}\) is used photoemission from \(A\) just stops but \(B\) still shows photoemission. When the latter wavelength is doubled, then photoemission from \(B\) just stops. Take \(hc=1240~\text{eV-nm}.\)
Work function of \(A\) is:
1. \(3.1~\text{eV}\)
2. \(2~\text{eV}\)
3. \(1~\text{eV}\)
4. \(1.5~\text{eV}\)
Work function of \(A\) is:
1. \(3.1~\text{eV}\)
2. \(2~\text{eV}\)
3. \(1~\text{eV}\)
4. \(1.5~\text{eV}\)
Subtopic: Einstein's Photoelectric Equation |
61%
Level 2: 60%+
Hints
Two metals \(A\) and \(B,\) when exposed to light of wavelength \(400~\text{nm}\) shows the photoelectric effect. However, when light of wavelength \(620~\text{nm}\) is used photoemission from \(A\) just stops but \(B\) still shows photoemission. When the latter wavelength is doubled, then photoemission from \(B\) just stops. Take \(hc=1240~\text{eV-nm}.\)
Work function of \(B\) is:
1. \(3.1~\text{eV}\)
2. \(2~\text{eV}\)
3. \(1~\text{eV}\)
4. \(1.5~\text{eV}\)
Work function of \(B\) is:
1. \(3.1~\text{eV}\)
2. \(2~\text{eV}\)
3. \(1~\text{eV}\)
4. \(1.5~\text{eV}\)
Subtopic: Einstein's Photoelectric Equation |
61%
Level 2: 60%+
Hints
Two metals \(A\) and \(B,\) when exposed to light of wavelength \(400~\text{nm}\) shows the photoelectric effect. However, when light of wavelength \(620~\text{nm}\) is used photoemission from \(A\) just stops but \(B\) still shows photoemission. When the latter wavelength is doubled, then photoemission from \(B\) just stops. Take \(hc=1240~\text{eV-nm}.\)
The fastest photoelectrons emitted, in all the experiments, have an energy of:
The fastest photoelectrons emitted, in all the experiments, have an energy of:
| 1. | \(3.1~\text{eV}\) | 2. | \(2.1~\text{eV}\) |
| 3. | \(1.1~\text{eV}\) | 4. | \(3~\text{eV}\) |
Subtopic: Einstein's Photoelectric Equation |
Level 3: 35%-60%
Hints
Photoelectrons are just emitted from the surface of a metal when light of wavelength \(400~\text{nm}\) is shone upon it. If light of wavelength \(310~\text{nm}\) is used, then the emitted electrons:
(take \(hc=1240~\text{eV-nm}.\))
(take \(hc=1240~\text{eV-nm}.\))
| 1. | will have a minimum energy of \(90~\text{eV}\) |
| 2. | will have a maximum energy of \(90~\text{eV}\) |
| 3. | will have a minimum energy of \(0.9~\text{eV}\) |
| 4. | will have a maximum energy of \(0.9~\text{eV}\) |
Subtopic: Einstein's Photoelectric Equation |
70%
Level 2: 60%+
Hints
All particles having a momentum of \(p\) are associated with wave-like behaviour and the wavelength, \(\lambda=h/p,\) where \(h\) is Planck's constant. Two particles \(A\) and \(B\) collide with each other, and come to rest. The de-Broglie wavelengths of \(A,B\) are \(\lambda_A,\lambda_B\) (before collision); while their masses are \(m_A,m_B.\) Then:
| 1. | \(\lambda_A=\lambda_B\) only if \(m_A=m_B\) |
| 2. | \(\lambda_Am_A=\lambda_Bm_B\) |
| 3. | \(\Large\frac{\lambda_A}{m_A}=\frac{\lambda_B}{m_B}\) |
| 4. | \(\lambda_A=\lambda_B,\) independent of \(m_A\) or \(m_B\) |
Subtopic: De-broglie Wavelength |
51%
Level 3: 35%-60%
Hints
Light having a frequency, which is half the threshold frequency for photoelectric effect, is incident on a metal: however, it is emitted from a sodium lamp. If laser light is used, with the same frequency, then it:
| 1. | will likely cause photoemission of electrons |
| 2. | will not cause photoemission of electrons |
| 3. | may or may not cause photoemission depending on the photon density |
| 4. | will cause photoemission only if its intensity is above a threshold |
Subtopic: Photoelectric Effect: Experiment |
69%
Level 2: 60%+
Hints
Which, of the following solid substances, will most likely show the photoelectric effect easily?
1. Potassium
2. Rubber
3. Plastic
4. Solid hydrogen
1. Potassium
2. Rubber
3. Plastic
4. Solid hydrogen
Subtopic: Photoelectric Effect: Experiment |
83%
Level 1: 80%+
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