Two conductors P and Q are tested in the laboratory. Their potential difference V is plotted against current I and in each case a straight line through the origin is obtained. The slope of the V-versus-I line for P is twice the slope for Q.
(i) Explain what physical quantity the slope of the V-versus-I graph represents.
(ii) Which conductor, P or Q, offers greater opposition to the flow of charge? Give reasons.
(iii) If both conductors are made of the same material and have equal cross-sectional area, what qualitative inference can you draw about their relative lengths?