Answer to Question #174823 in Molecular Physics | Thermodynamics for rica

Question

A copper wire has a resistance of 5 Ω at 20°C. What is its resistance if the temperature. Changed to 75°C

Answer 1

Given,

Resistance of the copper wire $(R_o)=5\Omega$

$T_1= 20^\circ C$

$R_2=?$

$T_2=75^\circ C$

$R=R_o(1+\alpha dT)$

temperature coefficient for copper $(\alpha)= +0.39\times 10^{-2}\Omega/^\circ C$

Now, $R_2=5(1+0.39\times 10^{-2}\times (75-20))$

$\Rightarrow R_2=5(1+0.39\times 10^{-2}\times 55)\Omega$

$\Rightarrow R_2 =5\times 1.21\Omega$

$\Rightarrow R_2 = 6.05 \Omega$