Question

The resistance of the conductor is 20ohms at 20°C and 50ohms at 500°C. Calculate the resist of these conductor at 80°C

Answer 1

Solution;

Given ;

$R_T=20\Omega$ at $T=20°c$

$R_{T'}=50\Omega$ at $T'=500°c$

Resistance at a given temperature;

$R_{T'}=R_{T}[1+\alpha(T'-T)]$

Substitute;

$50=20[1+\alpha(500-20)]$

Therefore;

$\alpha=\frac{1}{320}$

Now we obtained for R at 80°c;

$R_{T''}=20[1+\frac{1}{320}(80-20)]$

$R_{T''}=23.75\Omega$