- #1

Max Eilerson

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Using the leybold hall effect apparatus for silver http://www.leybold-didactic.com/phk/produkte.asp product ID: 58681. Dimensions

l = 0.064m (distance between contact), breadth 0.02m, and thickness 5E-5 m micrometers. Resistivity of silver [tex] \rho = 1.89x10^{-8} \Omega m [/tex]

Resistance [tex] R = \rho\frac{L}{A} [/tex]

[tex] R = 1.89x10^{-8} \Omega m \frac{0.064}{0.02.5x10^{-5}} = 0.0012 \Omega [/tex]

The instructions say to put a 20 A (2V) current across the sample, but from Ohms law [tex] V = IR [/tex] to get a 2V potentia difference we would need to pump a huge current through it. We had the resistance the contact resistances measured and they were in the microohm range, I'm told.

Since we haven't got the leybold suggested power supply, my professor is reluctant to put 20A across it because the above suggests it would melt (the silver strip is pretty expensive). Obviously I'm missing somethign simple here but I'm not sure what.

l = 0.064m (distance between contact), breadth 0.02m, and thickness 5E-5 m micrometers. Resistivity of silver [tex] \rho = 1.89x10^{-8} \Omega m [/tex]

Resistance [tex] R = \rho\frac{L}{A} [/tex]

[tex] R = 1.89x10^{-8} \Omega m \frac{0.064}{0.02.5x10^{-5}} = 0.0012 \Omega [/tex]

The instructions say to put a 20 A (2V) current across the sample, but from Ohms law [tex] V = IR [/tex] to get a 2V potentia difference we would need to pump a huge current through it. We had the resistance the contact resistances measured and they were in the microohm range, I'm told.

Since we haven't got the leybold suggested power supply, my professor is reluctant to put 20A across it because the above suggests it would melt (the silver strip is pretty expensive). Obviously I'm missing somethign simple here but I'm not sure what.

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