The number of electrons emitted from a metal when light shines on it is proportional to the intensity of the light. This means that if you double the intensity of the light, you will double the number of electrons emitted.
This is because the photoelectric effect is caused by the absorption of photons by electrons in the metal. When a photon is absorbed by an electron, the electron gains energy and may be emitted from the metal if it has enough energy to overcome the work function of the metal. The work function is the minimum energy required to remove an electron from the metal.
The intensity of light is a measure of the amount of light energy that is incident on a surface per unit area per unit time. The SI unit of intensity is the watt per square meter (W/m^2).
The relationship between the intensity of light and the number of electrons emitted from a metal is given by the following equation:
```
n = KI
```
where:
* n is the number of electrons emitted per second
* K is a constant that depends on the material of the metal
* I is the intensity of the light
This equation shows that the number of electrons emitted from a metal is directly proportional to the intensity of the light.
