The photoelectric threshold wavelength of silver is \(3250\times 10^{-10}~\text{m}.\) What will be the velocity of the electron ejected from a silver surface by the ultraviolet light of wavelength \(2536\times 10^{-10}~\text{m}?\)
(Given \(h= 4.14\times 10^{-15}~\text{eVs}\) and \(c= 3\times 10^{8}~\text{m/s}\))
1. \(\approx 0.6\times 10^{6}~\text{m/s}\)
2. \(\approx 61\times 10^{3}~\text{m/s}\)
3. \(\approx 0.3\times 10^{6}~\text{m/s}\)
4. \(\approx 0.3\times 10^{5}~\text{m/s}\)
(Given \(h= 4.14\times 10^{-15}~\text{eVs}\) and \(c= 3\times 10^{8}~\text{m/s}\))
1. \(\approx 0.6\times 10^{6}~\text{m/s}\)
2. \(\approx 61\times 10^{3}~\text{m/s}\)
3. \(\approx 0.3\times 10^{6}~\text{m/s}\)
4. \(\approx 0.3\times 10^{5}~\text{m/s}\)
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. | \(2:1\) |
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. | \(\dfrac{\lambda}{4}\) | 4. | \(\dfrac{\lambda}{6}\) |
Which of the following figures represent the variation of the particle momentum and the associated de-Broglie wavelength?
| 1. |  |
2. |  |
| 3. |  |
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. 1.3 V
2. 0.5 V
3. 2.3 V
4. 1.8 V
1. \(1:2\)
2. \(1:1\)
3. \(1:5\)
4. \(1:4\)
1. decrease by 2 times
2. decrease by 4 times
3. increase by 4 times
4. increase by 2 times
A source S1 is producing 1015 photons per sec of wavelength 5000 Å. Another source S2 is producing 1.02×1015 photons per second of wavelength 5100 Å. Then, (power of S2)/(power of S1) is equal to:
1. 1.00
2. 1.02
3. 1.04
4. 0.98
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