Thermal motion refers to the random motion of particles due to their thermal energy. In electromagnetism, it is the movement of charged particles in a conductor due to thermal energy. On the other hand, drift velocity refers to the average velocity of charged particles in a particular direction under the influence of an electric field.
Thermal motion and drift velocity are related in that they both involve the movement of charged particles. However, thermal motion is a random motion while drift velocity is a directed motion under the influence of an electric field. Additionally, thermal motion affects the magnitude of the drift velocity, as the higher the thermal energy, the higher the random motion of particles, and the lower the drift velocity.
As temperature increases, thermal motion also increases, resulting in a higher random motion of particles. This, in turn, affects the drift velocity, as the random motion of particles interferes with the directed motion under the influence of an electric field. Therefore, with an increase in temperature, the drift velocity decreases.
The drift velocity in a conductor can be affected by factors such as the strength of the applied electric field, the concentration of charged particles, and the properties of the conductor (e.g. resistance, length, and cross-sectional area). Additionally, external factors such as temperature and impurities in the conductor can also affect the drift velocity.
Electromagnetism is involved in thermal motion and drift velocity as it is the fundamental force responsible for the movement of charged particles in a conductor. The electric field created by the flow of current in a conductor influences the drift velocity of charged particles, while the thermal energy from electromagnetism causes the random motion of particles, affecting the overall drift velocity.