A technician is choosing a supply setting for a fixed resistor in a calibration unit. The resistor is kept at constant temperature.
During a test, the technician records these values.
| Potential difference across the resistor | Current through the resistor |
|---|---|
| 4.0 V | 80 mA |
The current through the resistor must not exceed 0.14 A.
The available potential difference settings are shown in the table.
| Available settings |
|---|
| 3.0 V |
| 6.0 V |
| 7.5 V |
| 9.0 V |
Calculate the highest available potential difference setting that the technician can use.
81 exam-style questions on Edexcel GCSE Physics 10.2 Resistance, covering 10.2.1 Current in a circuit and conservation at junctions, 10.2.2 Resistance and variable resistors, 10.2.3 Series and parallel resistance, 10.2.4 I–V characteristics of components, and 10.2.5 LDRs and thermistors. Each one has a worked solution and a mark scheme showing where the marks go.