General Physics> Define drift velocity and derive an expre...

Define drift velocity and derive an expression for it

palash singh , 10 Years ago

Grade Upto college level

7 Answers

Apoorva Arora

Last Activity: 9 Years ago

Thedrift velocityis the flowvelocitythat a particle, such as an electron, attains due to an electric field. It can also be referred to as axialdrift velocity. In general, an electron will propagate randomly in a conductor at the Fermivelocity.

Malavika Sajeev

Last Activity: 7 Years ago

Dreift velocity is the velocity attained by any particle such as electron when kept in an electric field.

Derivation:

Consider a cross section of conductor with length ‘l’ and area ‘A’. Let n be the no of electrons per unit volume.

The volume of conductor can be given as

V = Al

No. of electrons=nAl

Charge, q = ne= neAl

When connected with a battery current I pass through it which is equal to,

I = $\frac{q}{t}$ = $\frac{neAl}{t}$ $\because l/t=V$ _d

we can write this equation as:

I= enAV_d

Malavika Sajeev

Last Activity: 7 Years ago

Consider a conductor of length ‘l’. When electric field is applied, each electron experiances a force,

F= -eE ( $\because$ direction of force is opposite to direction of electric field)

It has an acceleration, $a=\frac{F}{m}$

i.e $a = \frac{-eE}{m}$

we know $v = a\tau$

$\therefore$ Drift velocity, $Vd = -\frac{eE}{m}\tau$

k.divakar k.divakar

Last Activity: 7 Years ago

The volume of the conductor =Av_dt=area×distance

Charge in that volume=Av_dtne. Since ne=q

Now,Av_dtne=q

Av_dne=q/t=I

Luckyraj Rathore

Last Activity: 7 Years ago

the average velocity with which free electrons drift under the influence of an external field. Vd = -eE r/m

Deepak

Last Activity: 6 Years ago

electrons move with an average velocity which is independent of time although electrons are accelerated this is the phenomenon of drift and velocity V_dis called drift velocity

Kushagra Madhukar

Last Activity: 4 Years ago

Dear student,

Please find the solution to your problem.

The drift velocity is the flow velocity that a particle, such as an electron, attains due to an electric field. It can also be referred to as axial drift velocity. In general, an electron will propagate randomly in a conductor at the Fermi velocity.

Consider a conductor of length ‘l’. When electric field is applied, each electron experiances a force,

F = – eE ( F = qE, and q = – e)

Now, acceleration, a = F/m = – eE/m

Hence, v = u + aT = aT = – eE/m x T (assuming u = 0)

Hence, drift velocity, v_d = – eET/m

Thanks and regards,

Kushagra