Photoelectric Effect

The photoelectric effect refers to the phenomenon where electrons are ejected from a material when it is exposed to light or electromagnetic radiation. This effect was first explained by Albert Einstein in 1905 and is a key concept in understanding the behavior of light and matter.

Energy of the Emitted Electron

The energy of the emitted electron in the photoelectric effect depends on the energy of the incident photon. The incident photon transfers its energy to the electron, causing it to be ejected from the material. The energy of the emitted electron is given by the difference between the energy of the incident photon and the work function of the material.

Work Function

The work function is the minimum amount of energy required to remove an electron from the surface of a material. It varies for different materials and is a characteristic property of the material. When the energy of the incident photon is greater than the work function, the excess energy is transferred to the electron as kinetic energy.

Explanation of the Correct Answer

The correct answer to the given question is option C, which states that the energy of the emitted electron is smaller than the incident photon. This is because the work function of the material must be overcome in order for the electron to be ejected.

When the energy of the incident photon is equal to the work function, the electron just has enough energy to overcome the binding forces of the material and be ejected. In this case, the kinetic energy of the emitted electron is zero.

When the energy of the incident photon is greater than the work function, the excess energy is transferred to the electron as kinetic energy. However, the maximum kinetic energy of the emitted electron is limited by the energy of the incident photon minus the work function. Therefore, the energy of the emitted electron is always smaller than the incident photon.

Conclusion

In summary, the energy of the emitted electron in the photoelectric effect is smaller than the energy of the incident photon. This is because the work function of the material must be overcome in order for the electron to be ejected. The excess energy of the incident photon is transferred to the electron as kinetic energy, but the maximum kinetic energy is limited by the difference between the energy of the incident photon and the work function.