(a) Explain what is meant by an ohmic conductor.
Important Questions on Resistance and Resistivity
Sketch a graph of resistance against voltage for a wire of pure iron kept at constant temperature. Label this line .
Sketch a graph of resistance against voltage for wire of impure iron, which is kept at constant temperature. Label this line .
Graph of resistance against voltage for a wire of pure iron kept at a constant temperature:
Graph of resistance against voltage for a wire of impure iron kept at a constant temperature:
Explain how the graphs would change if the wires were kept at a higher, but still constant, temperature.
The readings in this table are recorded from an experiment to measure the resistivity of silver.
Calculate the resistivity of silver.
The readings in this table are recorded from an experiment to measure the resistivity of silver.
| Diameter of the wire | 0.40 ± 0.2 mm |
| Length of wire | 2.25 ± 0.5 m |
| Resistance of wire | 0.28 ± 0.01 Ω |
Calculate the percentage uncertainty in each of the variables.
The readings in this table are recorded from an experiment to measure the resistivity of silver.
Use your table to calculate the absolute uncertainty in the value of the resistivity obtained in the experiment.
