Discovering Ohm's Law:

I have used the data to find the 1st data reduction. But I am not sure if it is correct.

Questions: 1. Check Data reduction 1 for valve of extracted R and conductivity for R.

2. The second Data reduction 2, Find the valve of extracted A and d.

3. As well for conductivity for A and d.

Data 1 : Voltage vs. Current 2 3 4 5 6 Voltage 1.001 2.001 2.00 2 4.000 5.010 6.00 0 Current MA 10 70 21:38 152. 09 142. 6 53 3 63. 80 Data reduction 1 941. 12 9 30 * 10 Value of extracted R = and OR = 2 : Resistance vs. Length Length 2m 4m 6m 8m 10m 0 . 852 Voltage 0. 73T Current 43. 0 24 . 88 17. UT 13. 30 10. 87 MA Resistance 6.017 0. 034 0. 05 0. 06 98 0 0855 G REV/i Data reduction 2 Value of extracted A = and CA = Value of extracted d = and od = R = P ( x) plot ( v,i , 'x )Voltage Ampes Current (mA) 1.001 0.01070 10.70 2.001 0.02138 21.38 3.002 0.03208 32.08 Current Vs Voltage 4.000 0.04260 42.60 0.07000 5.010 0.05330 53.30 0.06000 y = 0.0106x + 0.0001 R2 = 1 6.000 0.06380 63.80 0.05000 0.04000 Ampes i(A) 0.03000 0.02000 0.01000 0.00000 1 2 3 4 5 6 Voltage V(V) Length Resistance 0.017 Resistance Vs Length N 0.034 .09 0.050 0.08 y = 0.0085x - 0.0002 00 ) R2 = 0.9997 0.068 0.07 10 0.085 0.06 ce ( 0.05 in 0.04 0.03 0.02 0.01 0 2 4 6 8 10 12 Length (m)Experiment 1 getter Listsed rout (o) (gate arts juway and mur () DISCOVERING OHM'S LAW b do sersoont (b) 1.1 Purpose To find the current-voltage relations of conducting wires with various lengths. 1.2 Apparatus orda BOY no pigque er mut (). DC power supply, voltmeter and ammeter (two multi-meters), slide wire potentiometer board, met- ric graph paper and ruler or graphing software (e. g. Excel or Matlab /GNU Octave). 1.3 Theory If we apply the potential of V (in V, "Volts") to the ends of a conducting wire, a current i (in A, "Amperes") will be observed. Ohm's law states that the current is proportional to the voltage, or: R = (1.1) where the proportionality constant R is called the resistance of the conducting wire and is measured in 1, "Ohms" For a uniform conducting wire the resistance R is proportional to its length I and is inversely proportional to its cross-sectional area A, of vo R = PA (1.2) The proportionality constant p is called the resistivity of the wire and is measured in nm, "Ohmme- ter". The inverse of resistivity is called conductivity o, namely: 0 = - (1.3) The conductivity o is measured in 1/ (nm) or S, "Siemens". Combining Equations 1.1, 1.2, and 1.3, we find: VA _VA 1 = (1.4) O1.6 Questions 1. What conclusion can you draw from your data reduction? 2. Do the experimental points really fall on a straight line in your two plots? Give some discussion. Write the answers on the Data Sheet. DCPOWER SUPPLY 0.01 01.0 b To start point of measurement + To end point of measurement Power R Supply + A a Figure 1.1: Apparatus (left) and corresponding schematic diagram (right)