A Physics Student Performed an Experiment in Which the Potential

Multiple Choice

A physics student performed an experiment in which the potential difference V between the ends of a long straight wire was varied.The current I in the wire was measured at each value of the potential difference with an ammeter and the results of the experiment are shown in the table. Which one of the following statements is the best conclusion based on the data?

A) The resistance of the wire is 20 .
B) The wire does not obey Ohm's law.
C) The current in the wire is directly proportional to the applied potential difference.
D) The wire obeys Ohm's law over the range of potential differences between 5 and 30 V.
E) The wire obeys Ohm's law over the range of potential differences between 5 and 20 V.