Fall2023 Ohms Law Lab Online-2

Ohm’s Law Lab Online Purpose The purpose of this activity is to learn about Ohm’s Law, and to examine the different behaviors of Ohmic, and non-Ohmic materials when a voltage is applied to them. Theory Ohm’s Law tells us that resistance of an object is proportional to the voltage applied to it, and inversely proportional to the induced current passing through it. R = ∆V i A material is said to be Ohmic if the resistance of the material is independent of the applied voltage, meaning the ratio of ∆V i is constant. However, a material is said to be non-Ohmic if its resistance varies for changes in the applied voltage, meaning the ratio of ∆V i is not constant. The equation ∆V = iR is sometimes referred to as Ohm’s Law, but only in cases where the resistance is independent of the applied voltage. Ohm’s Law is not really a ‘law of nature’ but really just a description of a subclass of materials. Even for these materials if the temperature is changed enough the resistance will start to change for changes in the applied voltage. 1

Setup 1. Go to the following website: https://phet.colorado.edu/en/simulation/circuit-construction-kit-dc-virtual-lab 2. You should now see the following: 3. Click the down arrow to download the software. Once finished, you should see the following: 2

4. Click on the resistor in your circuit and set its resistance to 100 Ohms. 5. Click on the Potential Difference source (battery) in your circuit and set its voltage to 0.5 V. 6. Now take the voltage reading from the voltmeter and the current reading from ammeter and record those measurements in the Table. a. Repeat for when the Potential Difference source is set to 1.0 V, 5.0 V, 10.0 v, 20.0 V, 50.0 V, 75.0 V, and 100.0 V Analysis of Ohm’s Law Lab Online Name: Wyatt Collier Course/Section: PHY-1631-007 Instructor: Dale Bobar Table (20 points) Resistance R(Ω): 100 Ω V ( V ) i ( A ) 4

0.5 0.00 1.0 0.01 5.0 0.05 10.0 0.1 20.0 0.2 50.0 0.5 75.0 0.75 100.0 1.0 1. Using Excel and the data for the 100 Ω resistor, plot V vsi , with the equation for the trendline showing on the graph. Make sure to turn the graph in with your lab report. (20 points) 0 20 40 60 80 100 120 0 0.2 0.4 0.6 0.8 1 1.2 f(x) = 0.01 x − 0 Voltage vs Current V (Volts) Current (Amps) 2. What is the value of the slope of this graph? (15 points) The value of the slope of the graph is 0.01x because the equation of the line is y = 0.01 x − 0.0011 and m is equal to 0.01x. 3. What physical quantity does the slope represent and what are its units? (15 points) V = IR R = ( V I ) = ( voltage current ) = ( volts amps ) = Oh m ' s ( Ω ) 4. Is the slope constant or not? Is the material the resistor is made from Ohmic or non- Ohmic? (15 points) 5