You’ve been asked to determine whether a new material your company has made is ohmic and, if so, to measure its electrical conductivity. Taking a 0.50 mm × 1.0 mm × 45 mm sample, you wire the ends of the long axis to a power supply and then measure the current for several different potential differences. Your data are as follows:

Voltage (V) .................Current (A)
0.200 ..............................0.47
0.400 ..............................1.06
0.600 ..............................1.53
0.800 ..............................1.97
Use an appropriate graph of the data to determine whether the material is ohmic and, if so, its conductivity.