$1\, \mu A = \dots \dots \dots \,mA$

$(a)$ $A$ 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?

Why are alloys used to make standard resistors?

Three resistors $R_{1} = 5 \Omega$,$R_{2} = 10 \Omega$,and $R_{3} = 30 \Omega$ are connected in parallel to a $12 \; V$ battery. Which resistor will have the highest current flowing through it?

What are the factors on which the resistance of a conductor depends?

What are the factors on which the resistivity of a material depends?