A length of aluminum wire is connected to a precision 10.11 V power supply, and a current of 0.4218 A is precisely measured at 20.0°C. The wire is placed in a new environment of unknown temperature where the measured current is 0.4627 A. What is the unknown temperature?
Please show how you did it. Thanks!
2007-02-21 01:31:13 · 3 answers · asked by Minamoto 1 in Science & Mathematics ➔ Physics
we can assume that the temperature measuring device (a thermocouple) would be calibrated so that there is a linear response between temperature and current. From a we can say that the response is 20.0/0.4218= 47.4158 deg C/A.
We know that the current is 0.4627A, so that the temperature is 0.4627*47.4158= 21.939 degree C.
2007-02-21 01:38:52 · answer #1 · answered by The exclamation mark 6 · 0⤊ 0⤋
I think you can do this without complex maths - just do it as a comparison.
i.e. 0.4627 / 0.4218 = 1.096965386 (i.e ratio of the current)
The current has increased which means the resistanc eof the wire has gone down - hinting that the resistance has decreased, means a lower temperature.
Now, we just do 20 degrees / 1.096965386 = 18.232 degrees Celsius.
I'm sure that is accurate enough !!
2007-02-21 01:38:15 · answer #2 · answered by Doctor Q 6 · 0⤊ 0⤋
I'd start off by looking for a value for the temperature coefficient of resistance for aluminum...............
2007-02-21 01:38:31 · answer #3 · answered by lunchtime_browser 7 · 0⤊ 0⤋