Hi can anyone help me out with physics homework?
I need to find out the resistance of 0.31 mm diameter constantan wire. Constantan wire has a resistivity of 49 x 10-8 and the length is 1000mm.
The second question is as above but with a length of 500mm.
I have the equation of = pL/A but I keep getting different answers not sure what I am doing?
Can you help me out? I dont know what I am doing!
Thank you
J
2007-03-04 14:27:59 · 2 answers · asked by shetajan 1 in Science & Mathematics ➔ Physics
The likelihood is good that aakrzemi has your answer, assuming that he/she didn't make any multiplication error(s). AND
assuming your rho (resistivity) units are ohm-METER.
If the resistivity units are ohm-meter, plugging in the 500 and doing all the multiplication again SHOULD give you half of what
aakrzemi got for the 1000 mm. (If it doesn't, then either you or aakrzemi made a multiplication error.)
2007-03-04 15:36:09 · answer #1 · answered by answerING 6 · 0⤊ 0⤋
resistance = (rho*length)/(cross sectional area) or
R = pl/A. For the first part you answer would be:
R = ((49 x 10^-8)(1000 x 10^-3))/(pi(.00031/2)^2) = 6.492 Ohms
just change the 1000 in the first part to 500 in the second. Maybe you forgot to make sure everything was in meters.
2007-03-04 14:36:14 · answer #2 · answered by ADRRL 1 · 0⤊ 0⤋