Question

0.
4. According to free electron model the
resistance R of a wire of length L and area
of cross-section A is given by
(n is the free electron density, e charge on
electron and T the mean relaxation time)
mL
mA
a. R =
c. R =
nAe27
nle27
NL
MA
b. R =
d. R=
mAe27
n? Let​

Answer 1

Answer:

n, e, τ, m are representing electron density, charge, relaxation time and mass of an electron respectively of a wire.

Now, the resistance of the wire is given by:

R=

A

ρl

=

σA

l

, where σ is the electrical conductivity of the wire and σ=

m

ne

2

τ

.

So the resistance will be: R=

σA

l

=

ne

2

τA

ml