(a) The ohm's law states that the current carrying in a conductor is directly proportional to the voltage applied across the ends of the conductor, keeping the resistance constant. Circuit DiagramAccording to ohm's law; $V \propto I$Mathematically; $V = \mathbb{R}$where, $V =$ Voltage applied in volts$I =$ Current flowing in circuit in amperes.$R =$ Resistance of conductor (proportionality constant) Graphically; slope of will determine resistance of conductor.(b) Given, current flowing through conductor$\text{ (I) } = 0.35\,\text{A}$Potential difference across conductor $(V)$ $= 1.4\,\text{V}$We know, according to ohm's law, $V = I R$$\Rightarrow\; 1.4\,\text{V}\; = (0.35\,\text{A}) \times R$$\Rightarrow R\; = \left(\frac{1.4\,\text{V}}{0.35\,\text{A}}\right) = 4\,\Omega$Therefore, resistance of conductor is 4 ohms.