Light is shone on a metal and photoelectrons are emitted.
Can you tell me the three things from the listbelow which might cause the photoelectron emission to stop.
Decreasing the intensity of the light
Increasing the frequency of the light
Decreasing the wavelength of the light
Increasing the wavelength of the light
Changing the metal
Decreasing the frequency of the light
Increasing the intensity of the light
changing the metal, and decreasing the frequency to below the cutoff frequency. decreasing frequency is the same as increasing wavelength.
To determine which factors might cause the photoelectron emission to stop, we need to understand the principles of the photoelectric effect. The photoelectric effect refers to the emission of electrons from a metal when light is shone on it.
1. Decreasing the intensity of the light: The intensity of light refers to the amount of energy carried by each individual photon. Lowering the intensity means reducing the number of photons reaching the metal surface. Decreasing the intensity of light can reduce the number of photoelectrons emitted but will not stop the emission completely.
2. Increasing the frequency of the light: The frequency of light corresponds to the energy level of each photon. Increasing the frequency means increasing the energy of the photons. Higher energy photons may have sufficient energy to overcome the binding energy of the metal, resulting in increased photoelectron emission. Therefore, increasing the frequency of light is unlikely to cause the photoelectron emission to stop.
3. Decreasing the wavelength of the light: The wavelength of light is inversely proportional to its frequency. In general, decreasing the wavelength (increasing the frequency) of light will result in more energetic photons, potentially causing increased photoelectron emission. Therefore, decreasing the wavelength of the light is also unlikely to stop the photoelectron emission.
4. Increasing the wavelength of the light: Similar to the previous point, increasing the wavelength (decreasing the frequency) of light means lower energy photons. Therefore, increasing the wavelength of the light might lower the energy of photons and reduce photoelectron emission, eventually leading to the stoppage of emission.
5. Changing the metal: The photoelectric effect is dependent on the specific metal used. Different metals have different work functions (the energy required to remove an electron from the metal). Changing the metal can significantly affect the energy needed for photoelectron emission. It is possible that using a different metal might increase or decrease the photoelectron emission, but it can potentially stop the emission if the work function of the new metal is significantly higher.
6. Decreasing the frequency of the light: As mentioned earlier, lower frequency light corresponds to lower energy photons. Lower energy photons might not have sufficient energy to overcome the work function of the metal, leading to a decrease or complete halt in photoelectron emission.
7. Increasing the intensity of the light: Increasing the intensity of light means more photons are incident on the metal surface. This increase in the number of photons can lead to a higher number of photoelectrons being emitted. Thus, increasing the intensity of light is unlikely to cause the photoelectron emission to stop.
From the list, the three factors that might cause the photoelectron emission to stop are:
1. Increasing the wavelength of the light (decreasing the frequency)
2. Changing the metal
3. Decreasing the frequency of the light