The graph shows how the electric current I through a conducting liquid varies with the potential difference V across it. At which point on the graph does the liquid have the smallest resistance? D I B A V

Choice C is correct as proven by a series of steps stated below. Draw straight lines from the origin to each point A, B, C & D with a ruler. Each straight line drawn has a gradient equal to 1/R. Resistance (R) = Voltage (V) / Current (I)R=V/I I/V = 1/R The steepest graph will have the smallest resistance. The steeper the graph the greater the value of 1/R (gradient) & the lesser the value of R. In this case, Choice C has the steepest graph therefore it has the smallest resistance & is the correct choice. Choices A, B & D are incorrect because the graphs at each of those points is less steeper than that of Choice C (consider the series of steps stated above).

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Electricity | 2005 - O/N - 9702/1 | Q34