# Wheatstone Bridge Report

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• Topic: Centimetre, Uncertainty
• Pages : 2 (436 words )
• Published : October 13, 2012

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EC4
VI-1
I tabulated the data from sections V-1, V-2 and V-3. Using the equation σRx=Rx(1L1+L2L12)σL I determined σRx. These are values for DC power. R3=300Ω Unknown Resistor Number| L1 (cm)| L2 (cm)| σL (cm)| Rx=L2L1R3 ( )| σRx ()| Rm (Ω)| 1| 67.7| 32.3| .01| 143.1| .03| 147.7|

2| 58.4| 41.6| .01| 213.7| .06| 214.8|
3| 43.9| 56.1| .01| 383.4| .20| 385.5|
4| 23.5| 76.5| .01| 976.6| 1.2| 979.8|
For the unknown resistor 1, Rm is not in the range for my calculated value. For the unknown resistor 2, Rm is not in the range for my calculated value. For the unknown resistor 3, Rm is within the range for my calculated value. For the unknown resistor 4, Rm is not in the range for my calculated value. The discrepancy in my value could be because my location was not exact. This means current was present which would throw off my values. I assumed that I could measure the meter stick within .01 of a centimeter and I also assumed that all my values were recorded for a location of zero current. VI-2

I tabulated the data from V-4. These values are for AC power. R3=300 Ω, f= 500 Hz Unknown Resistor Number| L1 (cm)| L2 (cm)| σL (cm)| Rx=L2L1R3 ( )| σRx ()| Rm (Ω)| 1| 67.4| 32.6| .01| 145.1| .03| 147.7|

2| 58.7| 41.3| .01| 211.1| .06| 214.8|
3| 43.5| 56.5| .01| 389.7| .21| 385.5|
4| 23.9| 76.1| .01| 955.2| 1.7| 979.8|
My values for Rxac and Rxbc do not overlap but are close to each other. The uncertainties are comparable because you obtain them in the same way.

VI-3
I calculated the values for the unknown capacitors from section V-5 and calculated the uncertainty in Cx. C1=C2=.003 μF, f=500 Hz
Unknown Capacitor Number| C3 (μF) | σC3 (μF) | Cx=C2C1C3 (μF) | σCx (μF)| Cm (μF)| A| .0026| .0001| .0016| .00001| .00229|
B| .0045| .0001| .0045| .00001| .00429|
My values for the unknown capacitors and my recorded capacitors values do not overlap but...