Question

A certain electrical conductor has a square cross section, 2.0mm on a side and is 12m

long. The resistance between two ends is 0.072 (a) What is the resistivity of the

material? (b)If the electric field is 0.12V/m, what is the total current? (c) If the material

contains 81028 free electrons per m3

, find the average drift velocity of the electron.​

Answer 1

Answer:

Correct option is D)

Resistance of a conductor is given by

R=

l

ρA

..(i)

When l is the length of conductor. A its area of cross-section and ρ its resistivity

ρ=

l

RA

...(i)

Given R=0.072Ω

A=(2×2)mm

2

l=12m

Substituting the given values is Eq. (i) we get

ρ=

12

0.072×4×19

−6

=2.4×10

−18

Ωm