The work function of a metal is \(h\nu_0.\) Light of frequency \(\nu\) falls on this metal. The photoelectric effect will take place only if:
1. \(\nu\geq \nu_0\)
2. \(\nu>2\ \nu_0\)
3. \(\nu<\nu_0\)
4. \(\nu<\nu_0/2\)
| Assertion (A): | The work function of aluminium is \(4.2~\text{eV}\). Emission of electrons will not be possible if two photons, each of energy \(2.5~\text{eV}\), strike an electron of aluminium. |
| Reason (R): | For photoelectric emission, the energy of each photon should be greater than the work function of aluminium. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Why does the wave theory of light fail to explain the photoelectric effect?
| 1. | The photoelectric effect does not occur if the frequency of light is below a certain threshold, regardless of its intensity. |
| 2. | The maximum kinetic energy of the emitted electrons is unaffected by the intensity of the radiation. |
| 3. | There is no observable time delay between the radiation striking the surface and the emission of electrons. |
| 4. | All of the above factors. |
As the intensity of incident light increases,
| 1. | photoelectric current increases. |
| 2. | photoelectric current decreases. |
| 3. | kinetic energy of emitted photoelectrons increases. |
| 4. | kinetic energy of emitted photoelectrons decreases. |
The correct graph between photoelectric current \((i)\) and intensity \((I)\) is:
| 1. | |
2. | |
| 3. | 4. | |
If the frequency of incident radiations is doubled, then which of the following will increase?
1. Kinetic energy of the electron
2. Photoelectric current
3. Stopping potential
4. Both (1) & (3)
The figure below shows the variation of photocurrent \((i)\) with anode potential \((V).\) The three curves are due to:
| 1. | variation in the colour of light |
| 2. | variation in the frequency of light |
| 3. | variation in the intensity of light |
| 4. | variation in the photoelectric material |