advertisement

Physics B LAB: Graphical Analysis of Ohm’s Law Partners: Students will work in teams of three or less to complete this lab. Objective: Students will be able to determine the voltage of a cell from a graph of resistance versus current. Procedure: 1. 2. 3. 4. 5. Wire a circuit with a cell and one or more resistors. Draw a schematic diagram of the circuit and calculate the equivalent resistance. Record in the data table. Measure and record the corresponding current, connecting the ammeter in series. Do this 8 times without duplicating your resistance values. Up to 4 of these circuits may be a single resistor. The other 4 must be series, parallel, and combinations of series and parallel. Analysis: Rearrange the equation V = IR so that V is the slope of a “linear” equation (HINT: You’re going to have to divide, graphing the inverse of either current or resistance) Construct a graph from your data that corresponds to this rearranged equation. Calculate and clearly report the slope of the line. Conclusion: Is the line linear as Ohm’s Law predicts? How does this compare to the emf of 1.5 V for a D‐cell? What does this imply about the internal resistance of the cell? Rubric: Each student turns in their own paper, which includes a) b) c) d) ORHS Data table Rearrangement of equation Graph of data with line of best fit and triangle drawn to calculate slope Answers to questions in the conclusion section. Perkins, 2013