Answer:
The resistance of the silicon has to be 80 Ω and the iron must be 1120 Ω
Explanation:
Lets take
Temperature coefficients of resistivities or iron = [tex]5.\times 10^{-3} K^{-1}[/tex]
Temperature coefficients of resistivities or silicon = [tex]75.\times 10^{-3} K^{-1}[/tex]
The resistance of the iron increases a little as the temperature rises
The resistance of the silicon decreases a lot as the temp rises.
So we want the iron to be most of the resistance and have its increase in resistance exactly equal to the drop in resistance of the silicon.
Since the drop in the silicon is 15 times the rise in the iron ( 75 / 5 ) you want the iron to have 15 time the resistance of the silicon. And the total resistance has to be 1200Ω
1200/15 = 80
So
The resistance of the silicon has to be 80 Ω and the iron must be 1120 Ω
