Felix has placed some Aluminum (where the official looked up inferred absolute temperature is 236 Celsius) 24 gauge wire in a toaster oven at 275 degrees FahrenheitHe measures the resistance of the HOT wire to be 6.21 ohmsWhat is the length of the wire? Be sure to state the answer in feet to exactly the tenths place (ie rounded to ONE decimal places such that the number has the form of where represents some numerals that are CORRECT!) In other words, only express your answer with 4 numbers and a period/decimal point in the form of: .I don't know how to do it! Any help?
diameter of 24-gauge wire ordinarily 0.511 mm, at (I think) 25 Celsius Resistivity of aluminum 2.65 x 10^(-8) ohm meter at 20 C Temperature increases resistivity by a factor 1.0038 per degree C Temperature increases diameter by a factor 1.0000023 per degree C Now use R (resistivity)(length) / (pi r^2) after correcting both the diameter and the resistivity for the temperature changeThe only unknown in the equation is length; also note that the length you will calculate will be the HOT length, which perhaps they wanted corrected to room temperatures.
