Consider a conductor of fixed resistance R. The potential difference across it is changed successively, and the resulting currents are studied.
(i) Show that, for the same conductor, the ratio of two currents I1 and I2 equals the ratio of the corresponding potential differences V1 and V2.
(ii) A conductor carries 2A when 10V is applied. Using the relationship derived in part (i), determine the current when the potential difference is increased to 15V.
(iii) The same conductor is now connected to a supply where the potential difference is first increased by 25% and then decreased by 40% of the original 10V. Find the final current, keeping the resistance unchanged.