a student has two cylindrical resistors that are made of the same material. the student connects each resistor to a power supply and varies the potential difference across each resistor. the potential difference across the resistor and the current through it are measured until the current reaches 2a. the graphs above show the data for each resistor. which of the following single differences in the resistors could account for the data? responses the length of resistor x is greater than the length of resistor y.