126 University of South Alabama Physics PH 114/PH 115 Laboratory Manual 1.4 Preliminary Assignment 1) The distance between the two digital multi-meter probe tips is 1.8 x 10-2m . The potential difference between the probes is 1.11 V. Determine the electric field along the line defined by the probes. 2) A group of students trace out two equipotential surfaces and an electric field line as shown in Figure 1.4-1. A) Identify the polarity of each terminal. B) Calculate the electric field for each segment of the electric field line given that the distance between the two digital multi-meter probe tips is 2X10 2m. C) Determine the potential difference between the two equipotential lines by summing the voltages along the electric field line. Compare this value to the potential difference found by subtracting the voltages of the two equipotential lines. -+ -18-- 16 - 14 -+ + + 12 - + + + + + + + + + + + + + + + + 10- 8 Volts 2 Volts + + + + + + + + + + + + + + + + + + + + + + + + + + -+ 1.5 V A 6'T + + + + + + + + + 1.2 V X 1.1 V A90 + + + + -+ + + Figure 1.4-1: Sample data showing two equipotential lines (one at 8 Volts and another at 2 Volts) and one electric field line connecting the two equipotential lines