Question

The resistance of a metal wire of lenght 1m is 0.84ohm at 20degree celcius. if the diameter of the wire is 0.2mm , what will be the resistivity of the metal at that room temperature?​

Answer 1

d=0.2mm=2×10^-5m

r=10^-5m

r=(resistivity)×l/a

resistivity=r×a/l

=

$0.84 \times 2\pi {r}^{2} \div 1$

0.84×2×22/7×10^-5×10^-5÷1

${5.28}^{ - 9}$

Answer 2

Answer:

d = 0.2mm, r = 0.2/2 × 10^-3 m,

resistivity = ?

R= 0.84 ohm

using R = Resistivity × length / Area,

we get,

resistivity = resistance × area/ length

resistivity = 0.84 × 0.2/ 2 × 10^-3

-----> 0.084 × 10^ -3

thanks