Problem Solving Example

- The electric resistance of a certain resistor increases by 0.005ohms for every increase of 1C. Given that its resistance is 2ohms at 0C, find the equation relating the resistance and temperature. From the equation, find the resistance when T = 50C.

Solution:

Define the problem: Here we want to find an equation: R(T) = ?

Extract information: This is a linear relationship, so we can write:

R = mT + b

Information about the slope is given: m = 0.005/1 = 0.005

We use the information given to solve for the y intercept b.

2 = 0.005(0) + b

b = 2

So, the equation is: R = 0.005T + 2

And at 50C: R = 0.005(50) + 2 = 2.25ohms