Question

Two different wires have specific resistively, lengths, area of cross-sections are in the ratio $3:4$, $2:9$ and $8:27$. Then the ratio of resistance of two wires is

• A. $16:9$
• B. $9:16$
• C. $8:27$
• D. $27:8$

Answer 1

The correct option is B $9:16$

$R=\frac{\rho l}{a}$

$\frac{R_1}{R_2}=\frac{{\rho }_1}{{\rho }_2}\frac{l_1}{l_2}\frac{a_2}{a_1}=\frac{3}{4}\frac{2}{9}\frac{27}{8}=\frac{9}{16}$