Photoelectric current: why does it decrease?

In summary, the conversation discusses the relationship between intensity, wavelength, and photoelectric current in an experiment involving EM radiation falling on a metal surface. The speaker is confused about why decreasing the wavelength while keeping intensity constant causes a decrease in the photoelectric current, and speculates that it may be due to the energy needed for electrons to escape the surface. They also mention that in the experiment, a wavelength of 240 nm gives the maximum photoelectric current.
  • #1
BasilBassam
4
0
In my book it is stated.When you keep the intensity constant and decrease the wavelength the photoelectric current decreases but I can't understand why?

I thought it would stay the same since photoelectric current depends on the intensity of photons as more number oh photons means more e- released
 
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  • #2
Are you talking about stopping potentials experiments? As in when EM radiation falls on a plate A and a potential difference is applied across plates A and B such that B is more negative?
 
  • #3
Should that not be the other way around?

The electrons are not just being released from the surface. The ones further inside need to have more energy to escape the surface. If the wavelength of light is shorter electrons from further inside will make it out.
 
  • #4
The experiment is you supply light (photons) on a metal surface to release e-
then they said 240 nm wavelength of radiation gives Max Photoelectric current.After that they said Intensity is constant and wavelength is reduced causing the current to decrease but I simply can't understand why
 

FAQ: Photoelectric current: why does it decrease?

1. What is photoelectric current and why does it decrease?

Photoelectric current refers to the flow of electrons that are emitted from a material when it is exposed to light. This phenomenon is known as the photoelectric effect. The current decreases because the electrons that are emitted have a limited amount of energy, and once they are released, they cannot contribute to the current anymore.

2. What factors affect the decrease in photoelectric current?

Several factors can affect the decrease in photoelectric current, including the intensity and frequency of the incident light, the type of material being used, and the surface area of the material. Higher light intensity and frequency can result in more electrons being emitted, while certain materials may have a higher threshold for the photoelectric effect.

3. Can the photoelectric current ever increase?

Yes, the photoelectric current can increase if the incident light has a higher intensity or frequency, or if the material being used has a lower threshold for the photoelectric effect. Additionally, increasing the surface area of the material can also result in an increase in the photoelectric current.

4. How does the decrease in photoelectric current affect the efficiency of solar cells?

The decrease in photoelectric current can significantly affect the efficiency of solar cells. Solar cells rely on the photoelectric effect to convert light energy into electrical energy. If the current decreases, the amount of energy that can be converted also decreases, resulting in lower efficiency of the solar cell.

5. Can external factors, such as temperature, affect the decrease in photoelectric current?

Yes, external factors such as temperature can affect the decrease in photoelectric current. Higher temperatures can result in the release of more electrons, leading to an increase in current. However, if the temperature is too high, it can also cause the material to degrade, resulting in a decrease in current over time.

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