Drift Velocity Formula |
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\( v_d \;=\; \dfrac{ I }{ n \cdot q \cdot A }\) (Drift Velocity) \( I \;=\; v_d \cdot n \cdot q \cdot A \) \( n \;=\; \dfrac{ I }{ v_d \cdot q \cdot A }\) \( q \;=\; \dfrac{ I }{ v_d \cdot n \cdot A }\) \( A \;=\; \dfrac{ I }{ v_d \cdot n \cdot q }\) |
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| Symbol | English | Metric |
| \( v_d \) = Drift Velocity of Charge Carriers | \(ft\;/\;sec\) | \(m\;/\;s\) |
| \( I \) = Electric Current | \(A\) | \(A\) |
| \( n \) = Number of Charge Carriers per Unit Volume | \(ft^3\) | \(m^3\) |
| \( Q \) = Charge of Each Carrier | \(C\) | \(C\) |
| \( A \) = Area Cross-section of the Conductor | \(ft^2\) | \(m^2\) |
Drift velocity is the average velocity attained by charged particles, such as electrons, in a conductor when subjected to an electric field. In a conductor, the electrons move randomly due to thermal motion, but when an external electric field is applied, these electrons experience a force that causes them to slowly drift in the direction opposite to the field (because electrons carry negative charge). This drift is very slow compared to the random thermal speed of electrons, but it is responsible for the net flow of electric current through the material. The drift velocity depends on factors such as the current, the number density of charge carriers, the charge of each carrier, and the area cross-section of the conductor.
