(b) What is the resistance of a carbon rod at 25.8°C if its resistance is 0.0160 Ω at 0.0°C?

Video transcript

Hi everyone today, we are going to be determining the resistance of a heating element made out of Tungsten, which has a resistance of 40 at 600°C. So What we are interested at is the resistance at its original temperature of 10°C before it is heated. So it is known in this particular problem that the R Is going to be after it is heated at the of 600°C. What we are interested at is what is the previous or not and be not at the keynote of 10°C. So recall that we can find the resistance of a heating element at a certain initial temperature with its current temperature. Using this formula right here R equals R. Not multiplied by one plus alpha t minus t. Not just like so in this case are as the final resistance are not as the initial resistance alpha as the temperature coefficient, T is the final temperature and t naught is the initial temperature. So for tungsten the alpha, which is the temperature coefficient which is just a constant alpha is going to be 0.45 degrees Celsius to the part of minus one. Okay, so we have 10 out of 10 degrees Celsius t of 600. I'm just going to rearrange this so that it's easier for us. So are not is going to equal to R divided by one plus alpha t minus t. Not like So so we can actually start by just plugging all the known values to find what are are not is so our initial r is for the the bottom side is gonna be one plus alpha of 0.45 degrees Celsius report minus one of minus 10. Like so. And this will actually come up to an are not value of 10. and that will be the answer to this particular problem which is corresponding to option a just like so awesome. So it's resistance when the temperature is 10 degrees, Celsius is 10.9. Oh, so if you are still confused on this particular problem, we have other video lessons that you guys should check out and yeah that will be all for this particular problem. Thank you.