If the cross-sectional area of a conducting wire is doubled,what will be the effect on its resistance?

On what factors does the resistance of a conductor depend?

$V-I$ graphs for two wires $A$ and $B$ are shown in the figure. If both the wires are made of the same material and are of equal thickness,which of the two is of more length? Give justification for your answer.

$A$ $4 \, \Omega$ resistance wire is doubled on itself. Calculate the new resistance of the wire.

$A$ copper wire has a diameter of $0.5\, mm$ and a resistivity of $1.6 \times 10^{-8}\, \Omega \, m$. What will be the length of this wire to make its resistance $10\, \Omega$? How much does the resistance change if the diameter is doubled?

Resistivity of two elements $A$ and $B$ are $1.62 \times 10^{-8} \, \Omega m$ and $520 \times 10^{-8} \, \Omega m$ respectively. Out of these two,name the element that can be used to make
$(i)$ filament of electric bulb.
$(ii)$ wires for electrical transmission lines. Justify your answer in each case.