Q. No.When the light of frequency \(2\nu_0\) (where \(\nu_0\) is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is \(v_1\). When the frequency of the incident radiation is increased to \(5\nu_0,\) the maximum velocity of electrons emitted from the same plate is \(v_2.\) What will be the ratio of \(v_1\) to \(v_2\)?
1.
\(1:2\)
2.
\(1:4\)
3.
\(4:1\)
4.
\(2:1\)
1. \(5\lambda\)
2. \(\frac{5}{2} \lambda\)
3. \(3\lambda\)
4. \(4\lambda\)
An electron of mass \(m\) and a photon have the same energy \(E.\) The ratio of de-Broglie wavelengths associated with them is:
(\(c\) is the velocity of light)
2. \({c}\sqrt{(2 {mE})}\)
3. \( \frac{1}{{c}}\sqrt{\left(\frac{2 m}{E}\right)}\)
4. \(\frac{1}{{c}}\sqrt{\left(\frac{{E}}{2 {m}}\right)}\)
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. \(\frac{hc}{2\lambda}\)
2. \(\frac{hc}{\lambda}\)
3. \(\frac{2hc}{\lambda}\)
4. \(\frac{hc}{3\lambda}\)
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. | \(\leq 2.8\times 10^{-12}~\text{m}\) |
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. \(E \over c^2\)
1. \(6\lambda\)
2. \(4\lambda\)
3. \(\frac{\lambda}{4}\)
4. \(\frac{\lambda}{6}\)
Which of the following figures represent the variation of the particle momentum and the associated de-Broglie wavelength?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
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. \(1.5~\text{eV}\)
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. \(50\)
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