- #1
qim
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I have a question:
A pencil "lead" is made from non-metallic material which has a resistivity, at room temperature, of 4.0 x 10^-3 m.
A piece of this meterial has a length of 0.15 m and a diameter of 1.40 x 10^-3 m.
Show that the resitance of this specimen is 390 Ohm.
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Well I though of using R = rho x l / A
But then I read earlier that " by examining the dimensions of the resistor (assuming it is made from resistance wire instead of carbon as some are) we can also work out its resistance"
Does that mean that the question is a red herring, as the pencil lead is made from non metallic material?
Help...
Thanks
qim
A pencil "lead" is made from non-metallic material which has a resistivity, at room temperature, of 4.0 x 10^-3 m.
A piece of this meterial has a length of 0.15 m and a diameter of 1.40 x 10^-3 m.
Show that the resitance of this specimen is 390 Ohm.
-----
Well I though of using R = rho x l / A
But then I read earlier that " by examining the dimensions of the resistor (assuming it is made from resistance wire instead of carbon as some are) we can also work out its resistance"
Does that mean that the question is a red herring, as the pencil lead is made from non metallic material?
Help...
Thanks
qim