Question

the diameter of a copper wire is 2mm ,a steady current of 6.25 A is generated by 8.5 ×10 tothe power 28 per m cube electrons flowing throught it. calculate the drift velocity of conduction electrons.

Answer 1

Final. Answer :0.15 mm / s


Understanding :
1) CURRENT in a wire is given by
I. = neAV
where
I. = current
n = electron density
A = Area of cross section
V = Drift Velocity.

Steps
1) I = 6 .25 A
n = 8.25 * 10^(28)
radius = 1mm = 10^(-3) m
A = π * (10^-3)^2
= π *10^(-6) m^2

Th^n,
I = neAV
=> 6.25 = 8.5 * 10^(28) * 1.6 * 10(-19) * π * 10^(-6)
* V
=> V =
$\frac{6.25 \times {10}^{ - 3} }{8.5 \times 1.6 \times \pi} = 0.15 \times {10}^{ - 3} = 0.15mm \: per \: s$

Answer 2

Here is the Answer...

I = neAV

V=I/neA

V= 6.25/8.5×10^28×1.6×10^-19×π×10^-6

=0.14×10^-3

=0.15×10^-3

=0.15 mm/s