Question

define collision time

Answer 1

At the in individual particle level, the collision time is the mean time required for the direction of motion of an individual type particle to deviate through approximately as a consequence of collisions with particles of type.
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Answer 2

The collision time is the average time required for the collision between two particles.

Detailed answer

Usually, the time between a collision is very small and is very quick.

• The time is usually about $10^{-4}$M/s
• This is the process by which electrons are continuously colliding with the ions present inside the atom.
• The electrons that are drifting through the space are charged and produce a current.