Hello Aspirant,

The relationship between the electric current and the drift velocity is directly proportional.

It is expressed as,

I= Anev

where, I- electric current

A- uniform area of cross-section

e- charge on one electron

n- number of free electrons per unit volume of the conductor

v- drift velocity

Hope this helps.

Hello,

the drift velocity is directly proportional to current.

The drift velocity is the average velocity that a particle, such as an electron, attains in a material due to an electric field.

In general, an electron will propagate randomly in a conductor at the Fermi velocity.

An applied electric field will give this random motion a small net flow velocity in one direction.

{ref. Drift velocity - Wikipedia}

the drift velocity u = I /(n.A. q)

I = current

Where n is no. of electrons per m^3

A = cross sectional area of the wire

q = charge on an electron

copper wire is most common conductor.

Copper has a density of 8.94 g/cm3,

and an atomic weight of 63.546 g/mol, so there are 140685.5 mol/m3.

In one mole of any element there are 6.02×1023 atoms (Avogadro's constant). Therefore, in 1 m3 of copper there are about 8.5×1028 atoms (6.02×1023 × 140685.5 mol/m3).

Copper has one free electron per atom, so n is equal to 8.5×1028 electrons per cubic metre.

Assume a current I = 1 ampere, and a wire of 2 mm diameter (radius = 0.001 m). This wire has a cross sectional area A of 3.14×10−6 m2 (A = π × (0.001 m)2). The charge of one electron is q = −1.6×10−19 C.

The drift velocity therefore can be calculated: it comes to - in this wire the electrons are flowing at the rate of 23 μm/s

By comparison, the Fermi flow velocity of these electrons (which, at room temperature, can be thought of as their approximate velocity in the absence of electric current) is around 1570 km/s.

Thanku.