Q. No.A point source of light is used in a photoelectric effect. If the source is removed farther from the emitting metal, the stopping potential:
1.
will increase.
2.
will decrease.
3.
will remain constant.
4.
will either increase or decrease.
When the intensity of a light source is increased,
| (a) | the number of photons emitted by the source in unit time increases. |
| (b) | the total energy of the photons emitted per unit time increases. |
| (c) | more energetic photons are emitted. |
| (d) | faster photons are emitted. |
Choose the correct option:
| 1. | (a), (b) | 2. | (b), (c) |
| 3. | (c), (d) | 4. | (a), (d) |
Light of wavelength \(\lambda\) falls on a metal having work function \(\dfrac{hc}{\lambda_0}\). The photoelectric effect will take place only if:
1. \(\lambda \geq\lambda_0\)
2. \(\lambda \geq 2\lambda_0\)
3. \(\lambda \leq\lambda_0\)
4. \(\lambda < \dfrac{\lambda_0}{2}\)
1. \(10^{20}\)
2. \(10^{25}\)
3. \(10^{30}\)
4. \(10^{40}\)
| 1. | four times, doubled |
| 2. | doubled, remains unchanged |
| 3. | remains unchanged, doubled |
| 4. | four times, remains unchanged |
Which of the following statements about photons is incorrect?
| 1. | The rest mass of a photon is zero. |
| 2. | The momentum of a photon is given by \(h\nu/c.\) |
| 3. | The energy of a photon is \(h\nu.\) |
| 4. | Photons do not exert any pressure. |
1. \(mE^{1/2}\)
2. \(m^{-1/2}E^{1/2}\)
3. \(m^{-1/2}E^{-1/2}\)
4. \(m^{1/2}E^{-1/2}\)
1. \(6.4~\text{eV}\)
2. \(7.2~\text{eV}\)
3. \(3.2~\text{eV}\)
4. \(13.6~\text{eV}\)
| 1. | \(\dfrac{3}{2} \nu\) | 2. | \(2\nu\) |
| 3. | \(3\nu\) | 4. | \(\dfrac{2}{3} \nu\) |
In a photoelectric experiment, blue light is capable of ejecting a photoelectron from a specific metal while green light is not able to eject a photoelectron. Ejection of photoelectrons is also possible using light of the colour:
| 1. | yellow | 2. | red |
| 3. | violet | 4. | orange |
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