Electromagnetism Laboratory 3 Ohm's Law Experiment (A blind experiment) I. Introduction & Brief Description of the Concepts Ohm's law describes the relationship between the voltage and current across a particular material. For an Ohmic resistor, the voltage V (potential difference) across a resistor with resistance R has a particular relation with the current I going through the resistor. Therefore a graph of voltage versus current would reveal this relationship. In this lab, you will determine this relationship using the Vernier equipment and software. On the other hand, voltage across 'non-Ohmic' materials will have a different relationship. For example, if resistance changes as voltage changes, the graph of voltage versus current might show a curve with a changing slope. In the first part of this activity, investigate the relationship between the current and the voltage across a resistor in a DC circuit. In the second part, investigate the relationship between the current and the voltage across a resistor in an AC circuit. II. Lab Procedure, Data Taking and Preliminary Data Analysis a) Software to be used: In this lab we need we use the following APP: https://phet.colorado.edu/en/simulation/legacy/circuit-construction-kit-ac-virtual-lab. b) Virtual Equipment to be Used: 1. DC power supply the voltage can be changed (right click on the icon) 2. AC power supply : the AC maximum voltage as well as the frequency can be changed (right click on the icon) 3. Resistor : resistance can be changed (right click on the icon) 4. Wires 20.06060 5. Measurement devices: a) Voltmeter Voltage sensor. b) Ammeter 0.00 Amps Current sensor.6. The time graph generator (similar to an oscilloscope): time dependent D'a X variation of voltage difference across the resistor (notice the X two leads) and the current going through the circuit c) Lab Procedure & Data Taking: The goal from this lab is to study the behavior of the resistor when connected in closed circuit with (1) DC power supply and (2) AC power supply. Part I - Resistor and a DC Power Supply Virtual Equipment Setup: 1. Connect the DC power supply to a resistor using wires. 2. Connect the Voltage sensor to the resistor in parallel. 3. Connect the Current probe to the resistor in series. Voltage Sensor Current Sensor R A Power + 3 Supply Data Recording 1. Begin data taking manually set R = 10 2 and change the power supply voltage from OV to 5V, and record the values in table 1. Table 1. Describe the graphs: a. Voltage versus time: using the voltagetime graph in the simulation. b. Current versus time: using the currenttime graph in the Simulation. . Create a Voltage versus Current curve. _ Describe the time variation of both the voltage and the current\"? . Describe the voltage variation versus current? a. Fit the curve and determine the slope of the curve and record the values in table 2'? Is it the same value at different points {you can use excel} Part1? Resistor and an AC Pawcr Suggly Virtual\" Equipment Setup: 1. Redo Part I. but instead of using the DC power supply. use the AC power supply. mm Mending 1. Set the frequency to 0.5 Hz and the AC maximum voltage to 5V. 2. Data taking requires you to use the virtual stopwatch so that you can generate time dependent curves. 3. Describe the simulation graphs: a. Voltage versus time: using the voltage-time graph. b. Current versus time: using the currenttime graph. 4. Begin data taking manually and record cunent and voltage for each time value in Table 3. a. Describe the voltage variation versus current? b. Fit the curve and determine the slope of the curve and record the values in table 2? Is it the same value at different points? {you can use excel} 5. Change the frequency from [LS H: to 1.5 Hz then redo the above two steps (namely steps 3 and 4) and record your data in Table 4. 6. What is your conclusion regarding the Voltage versus Current graph? Table: 2 mm -_ -'-_ "I. Post-Lab: Final Den: Analysis and Conclusion What is the relationship between current and voltage in a simple resistor? Does the resistor behave differently when used in a DC or an AC circuit? . 1What does the slope represent? How signicant is the intercept? Your result will be compared to the actual resistance of the resistor used in this simulation. Using this value of the resistance, evaluate the accuracy of your measurement\"? 5. Is the time variation of the voltage across the resistor in phase or out of phase with respect to the current? rh'e-'F'Jf