**Why Intensity does not decide Stopping Potential?**

The stopping potential refers to the minimum potential difference required to stop the flow of photoelectrons emitted from a metal surface when it is exposed to electromagnetic radiation. The intensity of light, on the other hand, refers to the power per unit area of the incident light. Although both intensity and stopping potential are related to the photoelectric effect, they are independent of each other. Here's why intensity does not decide stopping potential:

**1. Nature of the Incident Light:**
The stopping potential depends on the nature of the incident light, specifically its frequency or wavelength. The kinetic energy of the emitted photoelectrons is determined by the energy of each photon, which is proportional to the frequency of the incident light. It is this energy that needs to be overcome by the stopping potential to stop the photoelectrons. Therefore, the frequency of light determines the stopping potential, not its intensity.

**2. Photon Energy and Electron Ejection:**
When photons strike the metal surface, they transfer their energy to the electrons in the metal. If the energy of a single photon is greater than the work function (the minimum energy required to remove an electron from the metal), an electron is ejected. The energy of the photon is directly related to its frequency, and increasing the intensity of light increases the number of photons but not their energy. Therefore, increasing the intensity does not affect the energy of individual photons or the kinetic energy of the emitted photoelectrons.

**3. Conservation of Energy:**
The stopping potential is determined by the energy conservation principle. The energy of a photoelectron is given by the equation E = hf - Φ, where E is the energy, h is Planck's constant, f is the frequency of the incident light, and Φ is the work function. The stopping potential is the potential difference required to prevent the photoelectron from gaining any kinetic energy. If the stopping potential is equal to or greater than the maximum kinetic energy of the emitted photoelectrons, then they will be stopped completely.

**Conclusion:**
In conclusion, the stopping potential is determined by the frequency (or wavelength) of the incident light and the work function of the metal. The intensity of light, which refers to its power per unit area, does not affect the energy of individual photons or the kinetic energy of the emitted photoelectrons. Therefore, intensity does not decide the stopping potential in the photoelectric effect.