Light is shone on a metal and photoelectrons are emitted.
Can you tell me the three things from the list below 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
thx trigger
Assistance needed.
The emission work function varies by type of metal. Photons must have sufficent energy, above the threshold energy (energy=constant*frequency). So reducing the frequency reduces the energy available to the photons, and at cuttoff, they cease. Long wavelengths is the same thing.
To determine the three things from the list that might cause the photoelectron emission to stop, we need to understand the phenomenon of photoelectric effect.
The photoelectric effect is the emission of electrons from a material when light of sufficient energy, known as photons, is incident on its surface. The energy of a photon is directly proportional to its frequency and inversely proportional to its wavelength.
Now, let's analyze each option from the list and see if it affects the photoelectron emission:
1. Decreasing the intensity of the light: The intensity of light refers to the number of photons hitting the material per unit area per unit time. Decreasing the intensity of light may result in fewer photons reaching the material, but it does not directly affect the energy of individual photons. Therefore, decreasing the intensity of the light does not stop the photoelectron emission.
2. Increasing the frequency of the light: As previously mentioned, the energy of a photon is directly proportional to its frequency. Increasing the frequency of light implies that the energy per photon increases. This can provide the photons with sufficient energy to overcome the work function of the material and release photoelectrons. Hence, increasing the frequency of the light would not stop the photoelectron emission but rather promote it.
3. Decreasing the wavelength of the light: Since the energy of a photon is inversely proportional to its wavelength, decreasing the wavelength of light increases the energy per photon. As a result, the photons become more energetic and have a better chance of causing photoelectron emission. Thus, decreasing the wavelength of the light would not stop but rather enhance the photoelectron emission.
4. Increasing the wavelength of the light: Similarly, increasing the wavelength of light decreases the energy per photon and makes it less likely to cause photoelectron emission. Therefore, increasing the wavelength of the light could potentially stop the photoelectron emission.
5. Changing the metal: The photoelectric effect is material-dependent, meaning different metals have different work functions (energy required to release electrons). If the chosen metal has a higher work function, it may require a higher-energy photon to cause photoelectron emission. Therefore, changing the metal to one with a higher work function could potentially stop the photoelectron emission.
6. Decreasing the frequency of the light: As mentioned earlier, the energy of a photon is directly proportional to its frequency. Decreasing the frequency of light decreases the energy per photon. Consequently, the photon might not possess enough energy to overcome the work function of the material, resulting in no photoelectron emission.
7. Increasing the intensity of the light: Increasing the intensity of light refers to more photons per unit area per unit time. If the light's intensity is increased, there will be more photons available to cause photoelectron emission. Therefore, increasing the intensity of the light would not stop but instead promote photoelectron emission.
Based on this analysis, the three things that might cause the photoelectron emission to stop are:
1. Increasing the wavelength of the light
2. Changing the metal to one with a higher work function
3. Decreasing the frequency of the light