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Lab 3: Ohm’s LawJacob DerrLab Partners: Evan Reid, Sierra JohnsonTA: David WeisbergerPHY 132Room: 366 Group #: 1Wed: 12:00-1:50Abstract:The purpose of this lab was to find the electric resistance and resistivity ofmany different samples. For portion 3 of this lab, a cylindrical conductor (graphite) was used. 5 data points for voltage and current were found for each of 5 different lengths, measured with a caliper between two alligator clips. The cross-sectional area (0.3456cm^2) was found by using the diameter (0.22cm) of the piece of graphite. The electric resistance (5.85Ω) was calculated from the slope after constructing a graph of current vs. voltage. Another graph was then made, this time plotting electric resistance vs. length. From this, the resistivity of the graphite was determined to be 0.57698Ω.The final graph also showed a non-zero intercept of 1.618 +/-0.07892. The meaning of this non-zero intercept is that anything below thelength of 1.618 will have no resistivity.
Objective:The purpose of this lab was to experiment with the concepts of resistivityand electric resistance. A key component of this lab was using Ohm’s Law, which can help determine the voltage drop across a resistor, as it is proportional to the current flow. If a sample obeys Ohm’s Law, it is said to be ohmic. For each of the three main portions in this lab, data consisting of current and voltage was calculated, limiting the voltage to a certain range. Afterwards, this data was used to find the electric resistance of each sample.