Question

PLEASE HELP!! PHYSICS QUESTION-DOES ANYONE KNOW HOW TO DO THIS WITH THE WORKING OUT?!?

Taking the resistivity of platinoid as 3.3 x 10-7 m, find the resistance of 7.0 m of platinoid wire of average diameter 0.14 cm.

Answer 1

Resistance of wire, R = 1.5 ohm

Step-by-step explanation:

Given that,

The resistivity of the platinoid wire, ρ = 3.3 x 10⁻⁷ ohm - meter

Length of the platinoid wire, l = 7 meter

Diameter of the wire, d = 0.14 cm = 0.0014 m

Radius of the wire, r = d/2 = 7 x 10⁻⁴ m

Therefore, core sectional area of the wire, A = π r²

= 1.539 x 10⁻⁶ m²

According to Pouillet's law, the resistance of a wire is given by the relation,

R = ρ · l/A ohm

Substituting the values in the above equation

R = 3.3 x 10⁻⁷
`(7)/(1.539 X 10^(-6))`

= 1.5 ohm

Hence, the resistance of the given platinoid wire is, R = 1.5 ohm