Question

two different wires whose specific are in the ratio 2:3 length 3:4 and radius of cross section 1:2 the ratio of their resistance is

Answer 1

Answer:2:1

Explanation:

See the picture and p=resistivity l=length r=radius a=area(πr²)

Answer 2

answer : 2 : 1

explanation : using formula, R = ρL/A

where ρ is specific resistance , L is length of wire and A is cross sectional area of wire.

if radius of wire is r then, A = πr²

so, R = ρL/πr² ⇒R ∝ ρL/r²

then, R1/R2 = (ρ1L1/r1²)/(ρ2L2/r2²)

= (ρ1/ρ2)(L1/L2)(r2/r1)²

here, ratio of specific resistance, (ρ1/ρ2) = 2 : 3.

ratio of length of wire, (L1/L2) = 3 : 4

and ratio of radius of wire, (r1/r2) = 1 : 2

then, R1/R2 = (2/3)(3/4)(2/1)²

= (1/2)(4)

= 2/1

= 2/1

hence, ratio of resistance of wires is 2 : 1