Stopping Potential

Definition

Stopping potential is the minimum potential difference required to just prevent the emission of photoelectrons from a metal surface when it is illuminated by light. It is the potential at which the kinetic energy of the emitted photoelectrons is reduced to zero, effectively stopping their ejection from the metal.

5 Must Know Facts For Your Next Test

1. The stopping potential is directly proportional to the frequency of the incident light and inversely proportional to the work function of the metal.
2. The stopping potential is the potential difference at which the maximum kinetic energy of the emitted photoelectrons is just reduced to zero.
3. The stopping potential can be used to determine the work function of a metal by measuring the relationship between the frequency of the incident light and the stopping potential.
4. The stopping potential is independent of the intensity of the incident light, as the photoelectric effect is a quantum phenomenon that depends on the energy of individual photons, not their number.
5. The stopping potential is an important concept in understanding the photoelectric effect and the behavior of electrons in materials.

Review Questions

• Explain how the stopping potential is related to the work function of a metal in the context of the photoelectric effect.
  • The stopping potential is directly related to the work function of a metal in the photoelectric effect. The work function is the minimum energy required to remove an electron from the metal, and the stopping potential is the minimum potential difference required to just prevent the emission of photoelectrons from the metal surface when it is illuminated by light. The stopping potential is proportional to the frequency of the incident light and inversely proportional to the work function of the metal, as the kinetic energy of the emitted photoelectrons is determined by the difference between the energy of the incident photons and the work function of the metal.
• Describe how the stopping potential can be used to determine the work function of a metal.
  • The stopping potential can be used to determine the work function of a metal by measuring the relationship between the frequency of the incident light and the stopping potential. According to the photoelectric effect, the kinetic energy of the emitted photoelectrons is equal to the difference between the energy of the incident photons and the work function of the metal. By plotting the stopping potential (which is proportional to the maximum kinetic energy of the photoelectrons) against the frequency of the incident light, the work function can be determined from the slope of the resulting line, as the work function is equal to the energy of the incident photons at the point where the stopping potential is zero.
• Analyze the significance of the stopping potential in understanding the nature of the photoelectric effect and the behavior of electrons in materials.
  • The stopping potential is a crucial concept in understanding the photoelectric effect and the behavior of electrons in materials. It demonstrates that the photoelectric effect is a quantum phenomenon, where the energy of the emitted photoelectrons is determined by the energy of the individual photons, not their intensity. The fact that the stopping potential is independent of the intensity of the incident light, but rather depends on its frequency, provides evidence for the particle-like nature of light and the quantization of energy. Additionally, the stopping potential can be used to determine the work function of a material, which is a fundamental property that reflects the energy required to remove an electron from the material. This understanding of the work function and its relationship to the stopping potential is essential for explaining and predicting the behavior of electrons in various materials and their applications in devices such as photodetectors and photovoltaic cells.

Related terms

Photoelectric Effect: The photoelectric effect is the emission of electrons from a metal surface when light of sufficient energy shines on it. The energy of the emitted electrons depends on the frequency of the light, not its intensity.

Work Function: The work function is the minimum energy required to remove an electron from a metal surface. It is the energy difference between the Fermi level and the vacuum level, and determines the potential required to stop the emission of photoelectrons.

Kinetic Energy: Kinetic energy is the energy of motion possessed by a moving object. In the context of the photoelectric effect, the kinetic energy of the emitted photoelectrons is determined by the frequency of the incident light and the work function of the metal.