Question

Drift velocity of electrons is due to
A) Motion of conduction electrons due to random collisions.
B) Motion of conduction electrons due to electric field \[\overrightarrow E \].
C) Repulsion to the conduction electrons due to inner electrons of ions.
D) Collision of conduction electrons with each other.

Answer 1

Hint:This is a concept question from drift velocity. By Applying the definition of drift velocity we can find the right option.



Complete answer:
Drift velocity is the average velocity attained by charged particles, (electrons) in a material due to an electric field (\[\overrightarrow E \]). The SI unit of drift velocity is the same as velocity which is m/s.

Hence, the correct option is Option B) Motion of conduction electrons due to electric field \[\overrightarrow E \].

Additional Information:
The relation between drift velocity and current is given below.
\[{v_d} = \dfrac{I}{{neA}}\]
\[{v_d}\]= drift velocity
I = current flow
n = free electron density
e = charge of an electron
A = cross sectional area
Mobility (\[\mu \]) of an electron is the drift velocity of an electron for a unit electric field (\[E\]). The equation for mobility is given below.
\[\mu = \dfrac{{{v_d}}}{E}\]
Current density is defined as the total amount of current passing through a unit cross-sectional conductor in unit time. The relation between drift velocity (\[{v_d}\]) and Current Density is given below.
\[J = \dfrac{I}{A} = \dfrac{{nA{v_d}e}}{A} = n{v_d}e\]
\[J = n{v_d}e\]
From this equation we can find that drift velocity and current density are directly proportional to each other.




Note: The drift velocity and current flowing through the conductor both increase as the intensity of the electric field increases. Drift velocity is directly proportional to electric field intensity.