A student investigates the electrical behaviour of a metallic conductor by studying its potential difference–current (V–I) characteristics.
(i) State the nature of the V–I graph that confirms the conductor obeys Ohm’s law.
(ii) Explain why the observed nature of the graph supports Ohm’s law.
(iii) Describe, without performing any numerical calculation, how the resistance of the conductor can be obtained from the V–I graph.