Physics, asked by tarikicmab7015, 1 year ago

Distinguish between relaxation time and collision time

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Answered by ABHINAVrAI
4

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(i) Relaxation time (τ): In the absence of an external electric field, the free electrons in a metallic substance will move in random directions, so that the resultant velocity of free electrons in any direction is equal to zero. By applying an external electric field on the specimen, the free electrons of the metal acquire a constant resultant velocity in the opposite direction to that of the applied electric field. If the field is turned off suddenly at t = 0, then the average drift velocity <vx>0 reduces exponentially to zero. The drift velocity after some time ‘t’ is:

where τ is called relaxation time. when t = τ then Equation (5.20) becomes:

(ii)Mean collision Time- The mean free time of a molecule in a fluid is the average time between collisions. The mean free path of the molecule is the product of the average speed and themean free time. 

OR

The mean free time of a molecule in a fluid is the average time between collisions. The mean free path of the molecule is the product of the average speed and themean free time. These concepts are used in the kinetic theory of gases to compute transport coefficients such as the viscosity.

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Answered by jaya8765
0

Answer:

Allow us first to begin with relaxation time. it is the shortfall of an outside electric field, the free electrons in a metallic substance will move in irregular headings with the goal that the resultant speed of free electrons toward any path is equivalent to nothing. While the Collision time it is the interim expected for the heading of movement of a singular sort molecule to veer off through roughly as a result of crashes with particles of type.

The relaxation time is firmly connected with the interim of trip among impact and furthermore to the mean free way of the conduction electrons, which is the typical distance of undisturbed movement between crash. All the crash processes happening in the electron gas might be made sense of through relaxation time. The crashes are brought about by warm or underlying flaws in the cross section. The relaxation time is presented as the trademark time overseeing the foundation of harmony, through impact, from an underlying upset circumstance wherein vx ≠ 0.

To know more about relaxation time visit the link given below:

https://brainly.in/question/13101648

To know more about collision time visit the link given below:

https://brainly.in/question/1198062

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