A thin copper wire carries current in two stages:
• Stage 1: a steady current of +3.0A flows for 2min.
• Stage 2: a current of −1.5A (opposite direction) flows for the next 4min.
(i) Taking the direction of Stage 1 current as positive, calculate the net charge transported through any cross-section during the entire 6min.
(ii) Find separately the number of electrons that pass the cross-section in Stage 1 and in Stage 2.
(iii) Determine the magnitude and direction of the average current for the whole 6min interval.
(iv) Explain the importance of algebraic sign in your answers to parts (i) and (iii).