2(b)], so that the length of the
combination is 2l The current flowing through the  combination is the
same as that flowing through either of the slabs If V is the potential
difference across the ends of the first slab, then V is also the potential
difference across the ends of the second slab since the second slab is
FIGURE 3 1 Charges +Q and –Q put at the ends
of a metallic cylinder