Question

Two resistors of same length have ratio of their cross-section area 1:2 .Resistors are made of same material.Which resistor has more resistance and how much?

Answer 1

Resistor R1......c.s.a-x (cross sectional area) Resistor R2......c.s.a-2x Resistance is in inversely proportional to square of cross section area. Let constant used be k. Therfore R1=k(1/x^2)..... R2=k(1/{2x}^2)=k(1/4x^2)...R1/R2=k(1/x^2)/ k(1/4x^2)=4/1 or 4:1(ans)