The Temperature Coefficient of Resistivity of Iron Is 5 $\degree$ C and That of Carbon Is -0

question 30

Multiple Choice

The temperature coefficient of resistivity of iron is 5.0 * 10-3 / $\degree$ C and that of carbon is -0.50 * 10-3 / $\degree$ C.When an iron wire and a carbon rod, each having the same 10 $\Omega$ resistance at 20 $\degree$ C, are cooled from that temperature to -80 $\degree$ C, the new ratio of the resistance of the carbon rod to the resistance of the iron wire at the lower temperature is:

• A)(-0.10.)
• B)+1.9.
• C)+2.1.
• D)(-10.)
• E)+10.