Answer
a). $(3) 9 $
b). $9ohm$
Work Step by Step
a). $R_{thin}=p_{thin}\times\frac{L_{thin}}{A_{thin}}$
$R_{thick}=p_{thick}\times\frac{L_{thick}}{A_{thick}}$
Length of both are same.
Also, resistivity of both are same since both are copper wires.
$d_{thick}=3d_{thin}$
Thus, $A_{thick}=9\times A_{thin}$
Hence, $\frac{R_{thin}}{R_{thick}}=\frac{A_{thick}}{A_{thin}}=9$
So, resistance of thinner wire is 9 times that of the thicker wire.
b). Given, $R_{thick}=1 ohm$
Then, $R_{thin}=9\times1=9ohm$
