Physics for IGCSE & O level - Electricity (Section 4 - No. 39)
If the cross-sectional area of a wire is doubled, what happens to its resistance (assuming other factors are constant)?
Doubles
Halves
Quadruples
Stays the same
Paskaidrojums
Resistance is inversely proportional to the cross-sectional area. If the area doubles, resistance is halved.