Correct Answer - Option 4 : Drift velocity
CONCEPT:
-
Saturation velocity: The maximum velocity of a charge carrier in a semiconductor is known as saturation velocity.
-
Instantaneous velocity: The rate of change of position for a time interval (very small).
- Terminal velocity: It is the maximum velocity that an object attained when it falls through a fluid.
-
Drift velocity: The average velocity that is gained by charged particles, (eg. electrons) in a material due to an electric field is called drift velocity.
- When there is no electric field, Subatomic particles like electrons move in random directions all the time.
- When electrons are subjected to an electric field, initially they do move randomly, but they slowly drift in one direction.
- The electrons move in the direction of the electric field applied, with drift velocity.
EXPLANATION:
- The average velocity attained by charged particles, (eg. electrons) in a material due to an electric field is called drift velocity.
- So the correct answer is option 4.
Drift velocity of the electrons is calculated by:
\(v=\frac{I}{neA}\)
where v is the drift velocity, I is the current in the wire, n is the number density of free electrons in the wire, A is the cross-sectional area of the wire, and e is the charge on one electron.
