Question

two wires of brass of diameter 1mm and 2mm have equal weight. the electric resistance will be in the ratio?

Answer 1

Resistance is the property of opposing the electric current through anything. There are several factors on which resistance depends which are follwing :-

Resistivity :- Resistance depends upon resistivity which is a proportionality constant and depends on nature of substance and temperature.
Temperature :- As the temperature increases, the value of resistivity increases so resistance increases . (In the case of conductors or simply metals).
Length :- Resistance is directly proportional to the length . So as the length increases the value of resistance increases.Cross Section Area :- Resistance is inversely proportional to the cross section area . So as cross section area increases the value of resistance decreases.

R1/R2=A2/A1
=π(r2)^2/π(r1)^2
=2^2/1^2
=4:1