An engineer investigates how the electrical resistance of a uniform strip of conductive polymer ribbon depends on its length.
The table below shows the experimental measurements recorded during the investigation:
| Length of ribbon (mm) | Voltage (V) | Current (A) | Resistance (Ω\OmegaΩ) |
|---|---|---|---|
| 50 | 12.0 | 2.40 | 5.0 |
| 100 | 12.0 | 1.20 | 10.0 |
| 150 | 12.0 | 0.80 | 15.0 |
| 200 | 12.0 | 0.60 | 20.0 |
| 250 | 12.0 | 0.48 | [Missing] |
Identify the independent variable and the dependent variable in this investigation.
(i) State the equation linking voltage, current, and resistance. (ii) Complete the table by calculating the missing value of resistance.
Describe the relationship shown by these results between the length of the polymer ribbon and its resistance, and explain how a graph of resistance (yyy-axis) plotted against length (xxx-axis) would support this conclusion.