Photoelectric emission:
Photoelectric emission is the phenomenon where electrons are emitted from a material surface when light of sufficient energy is incident on it. This process involves the transfer of energy from photons to electrons, resulting in the ejection of electrons from the material.

Factors affecting photoelectric emission:
Several factors influence photoelectric emission, including the intensity, wavelength, and frequency of the incident light, as well as the work function of the material.

Intensity of light:
The intensity of light refers to the amount of energy carried by the photons incident on the material surface per unit area per unit time. It is directly proportional to the number of photons incident on the surface.

Proportional relationship:
The number of electrons ejected per second, or the photocurrent, is directly proportional to the intensity of light. This means that increasing the intensity of light increases the number of electrons emitted, while decreasing the intensity reduces the number of emitted electrons.

Explanation:
When light interacts with a material surface, it transfers its energy to the electrons in the material. The energy of a photon is given by the equation E = hf, where E is the energy, h is Planck's constant, and f is the frequency of the light. If this energy exceeds the work function of the material, the electron can overcome the binding forces and be emitted.

The intensity of light is directly related to the number of photons incident on the surface. When the intensity of light increases, the number of photons incident on the material surface increases as well. As a result, more electrons are exposed to photons, increasing the chances of electron emission.

In contrast, when the intensity of light decreases, the number of photons incident on the surface decreases. Consequently, fewer electrons are exposed to photons, reducing the probability of electron emission.

Therefore, the number of electrons ejected per second, or the photocurrent, is directly proportional to the intensity of light. Increasing the intensity of light increases the number of photons incident on the surface, leading to a higher number of emitted electrons.

Conclusion:
In photoelectric emission, the number of electrons ejected per second is directly proportional to the intensity of light. Increasing the intensity of light increases the number of photons incident on the material surface, resulting in a higher number of emitted electrons.