Answer
a) $ 0.047 μΩ$ (Side to side)
b) $R=672 μΩ$ (End to end)
Work Step by Step
The formula for resistance is : $R=\frac{ρL}{A}$
a) This shows that resistance is inversely proportional to the area and when area increases, the resistance decreases. Therefore the resistance of 120 wires placed side to side to create a single strand is: $R = \frac{Resistance of Wire}{Number Of Wires}$ $R = \frac{5.60 μΩ}{120}$ Thus, The resistance is $ 0.047 μΩ$
b) However, if the wires are connected end by end, the area is the same but the length increases by a factor of 120 and since length is proportional to the resistance, the resistance increases by a factor of 120 as well.
Thus the resistance is $R= (Resistance of One wire)\times(Number of Wires)$.
$R = (5.60 μΩ)\times(120)$
$R=672 μΩ$