Question

Using the charts below, if you knew that a 1 mm diameter copper-nickel alloy wire can withstand a maximum load (before plastic deformation) of 78.54 N, and possesses an electrical resistance of 0.5 Ohms, then what is its length

Answer 1

Answer:

L = 10.32 m

Explanation:

The resistance of a copper-nickel alloy wire is given by the following formula:

$R = \frac{\rho L}{A}$

where,

R = Resistance = 0.5 Ω

ρ = resistivity of copper-nickel alloy = 3.8 x 10⁻⁸ Ωm

L = Length of wire = ?

A = cross-sectional area of wire = $\frac{\pi d^2}{4} = \frac{\pi(1\ x\ 10^{-3}\ m)^2}{4}$ = 7.85 x 10⁻⁷ m²

Therefore,

$0.5\ \Omega = \frac{(3.8\ x\ 10^{-8}\ \Omega.m)L}{7.85\ x\ 10^{-7}\ m^2}$

L = 10.32 m