Mathematics for IGCSE & O level - Proportion (Section 1 - No. 24)
The resistance (R) of a wire is directly proportional to its length (L) and inversely proportional to its cross-sectional area (A). Which equation describes this relationship?
R = kLA
R = kL/A
R = kA/L
R = k/(LA)
Explication
Directly proportional means multiply; inversely proportional means divide, so R = kL/A.