Drift Velocity Derivation

Drift velocity is defined as the average velocity attained by the particles (electrons) of a given material due to an electric field which is proportional to current. Ohm’s law can be expressed in terms of drift velocity as follow:

u=μE

Where,

u: drift velocity (m/s)

μ: material’s electron mobility (m2/V.s)

E: electric field (V/m)

Derivation of Drift velocity

Following is the derivation of drift velocity:

\(F=-\mu E\)

\(a=\frac{F}{m}=\frac{-\mu E}{m}\)

\(u=v+at\)

Here,

v = 0

t = T (relaxation time that is the time required by an electron to return to its initial equilibrium value)

\(u=aT\) (substituting for v and u)

\(∴ u=(\frac{-\mu E}{m})T\) (substituting for a)

This is the final equation explaining drift velocity.

But as the temperature increases, drift velocity of electrons increases in a metallic conductor.

This was the derivation of drift velocity. Stay tuned with BYJU’S and learn various other Physics topics.

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