PHY 114
Ohm’s Law
Krisztina Tope
M. Alcantar and K.Wully
12272, Group (#)
Chenou Zhang
2/24/2016
Abstract
In this lab students used voltmeters, ammeters, resistors with known resistance, rods with unknown
resistivity, and equipment to replicate a nonideal DC supply and circuit with respected internal and local
resistors to verify Ohm’s Law, exercise the equation for resistance, and observe the point of local power
maximization in the nonideal supply. Initially to verify ohm’s equation, students determined the
proportionality from the equation of resistance (R) to voltage drop (V) and current flow (I), R (ohms) = V
(volts) / I (amperes), and graphed 5 points of current flow v their respected voltage drop to use the slope
of the line to represent the experimental value of resistance and compare it to the resistance of the known
resistor. Finding a percent discrepancy of 1.19% from the experimental of 364.3 A and theoretical 360 A,
ohm’s law was successful verified. Upon exercising the resistance equation, Resistance (R) [in ohms] =
resistivity constant times length of the resistor (in meters) divided by the cross sectional area (in meters
squared), students used the known cross sectional area and 5 varied lengths to plot the calculated
resistance (from the I and V read from the meters) against the length to determine the resistivity value of
the rod with unknown resistivity. This was value was found to be
1.26
∗
10
−
5
. Last, with the nonideal