Q. No.Which of the following figures represent the variation of the particle momentum and the associated de-Broglie wavelength?
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2. |  |
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4. |  |
For photoelectric emission from certain metals, the cutoff frequency is \(\nu.\) If radiation of frequency \(2\nu\) impinges on the metal plate, the maximum possible velocity of the emitted electron will be:
(\(m\) is the electron mass)
| 1. | \(\sqrt{\dfrac{h\nu}{m}}\) | 2. | \(\sqrt{\dfrac{2h\nu}{m}}\) |
| 3. | \(2\sqrt{\dfrac{h\nu}{m}}\) | 4. | \(\sqrt{\dfrac{h\nu}{2m}}\) |
| 1. | \(6\lambda\) | 2. | \(4\lambda\) |
| 3. | \(\dfrac{\lambda}{4}\) | 4. | \(\dfrac{\lambda}{6}\) |
A photoelectric surface is illuminated successively by the monochromatic light of wavelength \(\lambda\) and \(\frac{\lambda}{2}\). If the maximum kinetic energy of the emitted photoelectrons in the second case is \(3\) times that in the first case, the work function of the surface of the mineral is:
[\(h\) = Plank’s constant, \(c\) = speed of light]
1. \(\dfrac{hc}{2\lambda}\)
2. \(\dfrac{hc}{\lambda}\)
3. \(\dfrac{2hc}{\lambda}\)
4. \(\dfrac{hc}{3\lambda}\)
If the kinetic energy of the particle is increased to \(16\) times its previous value, the percentage change in the de-Broglie wavelength of the particle is:
1. \(25\)
2. \(75\)
3. \(60\)
4. \(50\)
| 1. | \(V_0 /2\) | 2. | \(V_0 \) |
| 3. | \(4V_0 \) | 4. | \(2V_0 \) |
Radiation of energy \(E\) falls normally on a perfectly reflecting surface. The momentum transferred to the surface is:
(\(c\) = velocity of light)
| 1. | \(E \over c\) | 2. | \(2E \over c\) |
| 3. | \(2E \over c^2\) | 4. | \(E \over c^2\) |
When the energy of the incident radiation is increased by \(20\%\), the kinetic energy of the photoelectrons emitted from a metal surface increases from \(0.5~\text{eV}\) to \(0.8~\text{eV}\). The work function of the metal is:
1. \(0.65~\text{eV}\)
2. \(1.0~\text{eV}\)
3. \(1.3~\text{eV}\)
4. \(1.5~\text{eV}\)
1. \(\lambda_p \propto \lambda_e\)
2. \(\lambda_p \propto \sqrt{\lambda_e}\)
3. \(\lambda_p \propto \frac{1}{\sqrt{\lambda_e}}\)
4. \(\lambda_p \propto \lambda_e^2\)
Light of wavelength \(500~\text{nm}\) is incident on metal with work function \(2.28~\text{eV}\). The de-Broglie wavelength of the emitted electron is:
| 1. | \(< 2.8\times 10^{-10}~\text{m} \) | 2. | \(< 2.8\times 10^{-9}~\text{m}\) |
| 3. | \(\geq 2.8\times 10^{-9}~\text{m}\) | 4. | \(\leq 2.8\times 10^{-12}~\text{m}\) |
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