 In this video we'll be looking at the effect the temperature has on conductor resistance. So here we have a conductor that is 800 feet long. It's number 16 made of copper. In a previous video we worked out that its resistance worked out to be 3.22 ohms. Now that 3.22 ohms is calculated out at 20 degrees Celsius. However, oftentimes rooms will heat up and as heat increases, resistance often increases and that is called a positive temperature coefficient. So we're going to look to see what kind of effect this could have on the resistance of a conductor. So what we're going to use is this formula here. r sub c is equal to r sub o times alpha times delta t. Now we're going to look at what these are. This is your original resistance which is the 3.22 ohms. This symbol here is our coefficient of temperature. So we're going to see what that means in a second and this means the change in temperature from the 20 degrees that we've calculated out so far. So let's say that our room is actually 40 degrees. This calculation here was based off of 20 degrees so our change in temperature is going to be 20 degrees. Also when we're dealing with a copper conductor it has a temperature coefficient of 0.00393. That's its temperature coefficient. Now you're not going to be expected to memorize that obviously. You're going to probably look on Google or pull out your phone or ask somebody super smart what that is. But that's going to be for copper. If we're dealing with aluminum, brass, gold, iron, lead, tungsten, silver, they all have different temperature coefficients. So this is only for copper not for anything else and you could look up what they are for any other metal that's out there. So that's our coefficient which is this. Our 40 degrees is 20 degrees more than it was before so watch out for that. It's at 40 degrees the room this was calculated off of 20 therefore our delta T here, our change in temperature is 20 degrees. So we plug in what we know. We know that our original was 3.22 ohms. We know that the coefficient is 0.00393 and we know we had a change in temperature of 20 degrees. So our resistance change works out to be, rounded off, it works out to be 0.25 ohms. That's how much the resistance has changed so we need to take that into account with the actual resistance here, the original resistance. We need to go ahead and add this to the original resistance. So to calculate out what the resistance is now at 40 degrees C, we take our change in resistance and we add it to our original resistance and we get our new resistance. In this case that's going to be 3.47 ohms. So again, you take your original resistance, multiply it by the coefficient of temperature for the material you're using, whether that be copper, aluminum, silver, any of those. And then the change in temperature from 20 degrees, you get your change in resistance and then you add that to your original resistance to get your new resistance.