Physics Lab Report: Resistance and Ohm’s Law
Physics Lab Report: Resistance and Ohm’s Law
Resistance and Ohm’s Law
Resistance Measurements
The resistance is identifying by the color code (Rcode). You can find the color code table and the figure example below.
| Color | Number | Multiplier | Tolerance |
| Black | 0 | 1=100 | |
| Brown | 1 | 101 | |
| Red | 2 | 102 | |
| Orange | 3 | 103 | |
| Yellow | 4 | 104 | |
| Green | 5 | 105 | |
| Blue | 6 | 106 | |
| Violet | 7 | 107 | |
| Gray | 8 | 108 | |
| White | 9 | 109 | |
| Gold | 10-1 | 5% | |
| Silver | 10-2 | 10% | |
| None | 20% |
2. Ohm’s Law
Equipment:
4 AA battery holder
4 AA battery (1.5 volts)
10 75 Ω resistors
1 DC analog ammeter
1 digital voltmeter
-Set up a DC series circuit with 75 Ω the Battery and the “wire wound” resistor provided.
-Connect an ammeter in series with the resistor and a voltmeter in parallel with the resistor.
-read the Ammeter and Voltmeter and Right down the value in First Row of Table.
| Current I (ammeter value) | Voltage V (voltmeter Value) |
| I = | V = |
| I = | V = |
| I = | V = |
| I = | V = |
– Add Another battery in series to frist one and again try to read the numbers voltmeter and ammeter and write down the numbers in second table.
Batteries in Series
-repeat the experiment for 3 batteries and 4 batteries in series and for each situation read the value for ammeter and voltmeter and write down the value in 3th and 4th row of table .
-Plot V vs I. (V vertical and I horizontal) and find the slop of graph (Y4-Y1) / (X4-X1). this number should be close to 75Ω.
-Calculate the percentage error. (theoretical number is 75.