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प्रश्न
Is it always possible to see the photoelectric effect with a red light?
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उत्तर
No, it is not possible to see the photoelectric effect with a red light.
Explanation:
The energy required to rip an electron out of its orbital is equal to the electron's work function, and photons in red light lack this energy. Because light behaves like particles rather than a continuous stream, even very high-intensity red light will never be able to overcome an electron's work function (in this case), because each photon fails to do so. This demonstrates the particle behaviour of light. The photoelectric effect demonstrates the particle nature of light, and even very intense or prolonged exposure to red light will not cause the effect if the photon energy is insufficient.
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संबंधित प्रश्न
Using the values of work function given in the following table, tell which metal will require the highest frequency of incident radiation to generate photocurrent.
Typical values of work function for some common metals
| Metal | Work function (in eV) |
| Potassium | 2.3 |
| Sodium | 2.4 |
| Calcium | 2.9 |
| Zinc | 3.6 |
| Silver | 4.3 |
| Aluminium | 4.3 |
| Tungsten | 4.5 |
| Copper | 4.7 |
| Nickel | 5.0 |
| Gold | 5.1 |
Given the following data for incident wavelength and the stopping potential obtained from an experiment on the photoelectric effect, estimate the value of Planck's constant and the work function of the cathode material. What is the threshold frequency and corresponding wavelength? What is the most likely metal used for emitter?
| Incident wavelength (in Å) | 2536 | 3650 |
| Stopping potential (in V) |
1.95 | 0.5 |
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