Why do we use copper and aluminium wire for the transmission of electric current?

What happens to the resistance of a conductor when the length of the conductor is reduced to half?

$(a)$ $A$ Nichrome wire of length $L$ and radius $r$ has a resistance of $10 \, \Omega$. How would the resistance of the wire change when:
$(i)$ only the length of the wire is doubled?
$(ii)$ only the diameter of the wire is doubled? Justify your answer.
$(b)$ Why are the elements of electrical heating devices made up of alloys?

The resistance of a piece of rubber is higher than that of a piece of copper of the same dimensions.

What is the symbol used to denote the unit of resistance,ohm?

State the formula correlating the electric current flowing in a conductor and the voltage applied across it. Also, show this relationship by drawing a graph. What would be the resistance of a conductor, if the current flowing through it is $0.35 \ A$ when the potential difference across it is $1.4 \ V$?